A Talk with Kenneth Paul Rosenberg, MD Author of Infidelity: Why Men and Women Cheat

Why did you write this book?

For nearly twenty years, people have shown up at my consultation room for treatment for compulsive sexual behavior. My patients are generally men and some women with seemingly great marriages, great families, great careers. But they had this secret of a self-destructive quest for sex.

Being a specialist on addiction, I became fascinated about how easily all genders can develop an irrational exuberance for certain lovers and sexual encounters, even when the consequences are devastating. Still to this day, it is mind-boggling, even to me, how otherwise rational and cautious people could become addicted to dysfunctional love and put their lives on the line for new sex. As a result, I decided to write a book that not only pertains to those with compulsive and impulsive disorders like sex addiction, but which pertains to us “normal” folks. With cheating and furtive sex occurring so often, I thought that it would helpful to understand what motivates these behaviors and how we can prevent them and fix ourselves.


In your book, you discuss the biology of infidelity. Do some people cheat because they have a higher biological sex drive than others, or is it because of their psychology?

Both! The book details our evolutionary, biological desire to cheat, but what drives people is not just the biological urge for sex, but the need to feel strong and validated.  What we call “sex” often has little to do with actual sexual gratification. Orgasm, in the case of men, lasts for a matter of seconds, for women, rare;y longer than a minute. Much of what drives us toward sex is not orgasm, but intrigue, excitement, desire, a quest for validation and a sexualized attempt to prove one’s power over others. Another point that I repeatedly make in my book is that many people are driven toward self-destruction.


What’s the source material for your book?

I’ve tried to convey what I have learned though my own clinical work and research. I’ve been a psychiatrist for twenty-five years, studying, researching, and treating sexual disorders and addictions. So of course that has affected how I look at relationships. In the book, I relay real stories I’ve heard from patients and even from friends, keeping it all anonymous. In addition, in writing the book, I interviewed dozens of scientists who are studying fidelity and infidelity and interviewed other therapists who are experts on fidelity, infidelity, polyamory, BDSM (bondage, domination, submission, and masochism), and family therapy.


Could you break down the different parts of your book?

The first third of the book talks about desire and the role of brain chemistry. The second third of the book explains the nuances that drive some people toward affairs. In the last third of the book, I offer concrete suggestions and even some “rules” that help us move toward healthy relationships. Throughout the book and particularly in the last chapters, I argue that the desire for another lover is normal, and while that doesn’t pardon the philanderer, we need to understand the inner workings of our minds. In the final chapters, I talk about how to keep your primary relationship even after an affair. However, I explain how even if the affair destroys your relationship, you can certainly prevent it from destroying your life (as often happens).


How does one know if they have crossed the line from normal philandering into compulsive or addictive philandering?

To desire another lover is normal. Among heterosexual married people, 20% of men and 15% of women stray. Among unmarried dating folks, over 50% stray. Generally speaking, cheating is pretty common. However, if do you repeatedly in a way that feels out of your control and unmanageable, you’re now in the arena of self-destructive and compulsive behavior.


Many normal people are unhappy if they remain monogamous. Are you arguing for fidelity?

My book is not a diatribe for monogamy, but I argue that you just can’t lie to your partner about what you do. By the way, being unhappy in a relationship is one reason why some people cheat, but unhappiness is just one part of the puzzle. Over half of adulterous men and a third of adulterous women report being in happy or very happy marriages. So, you need not be dissatisfied with your partner to cheat.  


What is an “emotional affair”?

What happens when men and women, or people who are attracted to each other, are best friends, the relationships are deep and loving, and there is no sex involved? Everyone has their own opinion on this, but there are some telltale signs of trouble: The friendship, or at least the extent of it, is kept secret from your spouse. The relationship is filled with stolen moments of longing, and complaints about each others’ romantic partners. The relationship competes with and undermines the primary relationship.  In these circumstances, the relationship no longer qualifies as just a friendship even if sex is not (overtly) on the table. At that point, it qualifies as an emotional affair.  


Do men and women cheat for different reasons?

Men often cheat just for sex and women often cheat for an emotional connection. But seismic sexual and relationship shifts are unfolding in our society. And the roles of men and women are correspondingly changing. As a consequence, the motivations for and frequency of cheating are becoming more similar among men and women.


Can you tell us some of the biological data that leads people to cheat?

When it comes to desire, the familiar is not a turn-on. In many replicated studies, heterosexual women and men sniffed the T-shirts of several anonymous gender-opposite people, and chose which ones they felt were the sexiest. Overwhelmingly the participants selected T-shirts of the people who were genetically different from them in a specific part of the immune system called the major histocompatibility complex. So, by and large, we end up married to people from our tribe, but lust after people from other tribes.


Can you can tell us about the biological animal model for fidelity and infidelity?

While roughly 3% of mammals stay together after sex to rear their offspring, most venture off to have sex with other animals throughout their lives. There is one type of rodent—a particular species of voles—that was thought to be faithful for life. These rodents are especially interesting because they are nearly identical to another breed of voles that don’t stay together after procreation. The single great difference between the faithful and cheating breeds of voles was in specific regions of the brain containing vasopressin receptors and oxytocin receptors.  The plot thickens, though—when researchers looked closer, they found 20% of so-called monogamous prairie voles do in fact stray, even though the monogamous voles still remain socially bonded to their mates and offspring.


In the book, you write a lot about the lure of the new partner. Can you give an animal model?

Drop a male rat into a cage with a female rat who’s in heat and the two will copulate repeatedly until sexual exhaustion. Drop a new rat in the cage, the previously exhausted, opposite gender rat gets a second wind, and wants to have sex with the new rat in the cage. The appeal of a new mate over a pre-existing mate can be seen up and down the phylogenetic spectrum, in many species, from insects like beetles to primates.  The appeal of a new mate appears true of both males and females. This phenomenon (called the Coolidge effect after a joke about then-President Calvin Coolidge and his wife) is an ancient biological program aimed at seizing genetic opportunities, driven by a neurological mechanism whereby potent brain chemicals jolt a “sexually satiated” animal to continue to copulate.

The Coolidge joke goes like this: While touring a farm, First Lady Grace Coolidge noticed a rooster mating frequently. When she asked how often that happened, the attendant answered, “Dozens of times each day.” Mrs. Coolidge said, “Tell that to the president when he comes by.” The president then took the same tour, and was informed of the rooster’s frequent mating habits.  Upon hearing that the president asked, “Same hen every time?” The reply was, “Oh, no, Mr. President, a different hen every time.” President: “Tell that to Mrs. Coolidge.”


What is your argument for an addictive model for love and sex?

The brain’s addictive centers were not created to get us addicted to cocaine or heroin. Instead our brains evolved to get us hooked on the essential ingredients for the survival of our species: food, sex, and love. In order to entice a mother to risk her own life to give birth to and take care of those babies, the mammalian brain needed to have the social bonding system linked to the brain’s reward center. All mammal species (from rats to humans) have this maternal bond. Scientists think the same brain circuits that get directed toward caring for one’s young also get directed toward other individuals, including sexual partners. A loving attachment connection is like heroin to us. Once we have it, we don’t want to give it up. And if it gets taken away, our brains go into love withdrawal.


In your book, you describe how the reward chemical of the brain, dopamine, plays a role in driving us toward sex and social bonding. Is there evidence that differences in the brain receptor play a role in determining who is unfaithful?

The association between dopamine genes and infidelity was confirmed by Justin Garcia and his colleagues at Binghamton University in 2010 who studied 197 young adults and found that men and women with longer dopamine genes had more one-night stands.  Dr. Garcia reported that people with the long dopamine gene are more likely to have infidelity and casual sex. The long gene folks had dopamine receptors that require more dopamine to have the same effect as that experienced by a non-thrill-seeking person. For them to get a rush, they require more sensation-seeking behaviors to kick up their dopamine levels. Think of this dopamine receptor like a big well that can contain lots of water. The well doesn’t function properly until it is filled up. And what fills up these long dopamine receptors is lots of excitement.


You say that the internet and the cell phone is a dopamine multiplier. Can you explain this?

One of the first smart phones, called Blackberries, were known as “crackberries” as a tongue-in-check reference to how they were supposedly as addictive as crack. Today, the Internet, whether accessed by smart phone or computer, creates so much instant gratification and dopamine release that it would be apt to call it a magnifier of the dopamine reward centers. Even without googling anything related to sex, the Internet, in and of itself, offers instant gratification and provides a place that can consume many waking hours. Combine the Internet’s inherent compulsion loop and instant gratification along with the innate rewards of sex and we can understand why the combination of sex and Internet is so potent. A dopamine multiplier.


Let’s talk about the practical matter of what to do if your partner cheats. To start off, what can I expect if I suddenly discover that my partner is cheating?

An estimated 90% of partners never find out about the cheating. For those 10% who do, the ramifications can be dramatic. Even for the cheater, their spouse’s discovery of their affair can be the worst moment of their lives. As a betrayed spouse, you may develop a Post-Traumatic Stress Disorder or PTSD, with flashbacks, nightmares, and dissociation (meaning feeling unreal or out of it). You might experience the signs of clinical depression, such as weight loss, depressed mood, and sleeplessness. You could have fleeting thoughts of suicide.


Now, what should I expect if I am the one who is caught cheating?

At first, you will likely minimize your philandering behaviors. You will deny. If you’re a cheater, you’re in the habit of manipulating people. Despite knowing it is wrong, you will be inclined to continue to manipulate. You may even do what is called “gaslighting.” You tell your accuser lies and false justifications like, “I’m not having an affair. You’re just trying to control me.” Another technique used by the gaslighting spouse is to focus their accuser on the facts of the case that are incorrect, while withholding incriminating information. An example would be saying to your wife, “I never had sex with Susie. I never even had the slightest interest in her. You’re out of your mind! You’re paranoid!” Well maybe you never had sex with Susie, but you had oral sex with Paula and kissed Jane, none of which your wife knows about. You met Celia at the airport during your last business trip, which you never told her either. You confided about your marital problems to sexy Samantha, which your wife doesn’t know.  Not only will that approach fail, it’s a crappy way to treat someone—especially someone to whom you’ve pledged your love.


If my spouse cheated, what do I tell other people?

My prescription is to pause before you take steps that might cause further damage. If you’re a betrayed spouse, you may be seeking vengeance, processing rejection, or perhaps struggling with PTSD. As with most things regarding infidelity, there is no single, easy answer. Be discreet, and be thoughtful.


But if I’m a betrayed spouse, surely I need lots of people to talk to, yes?

In asking for support, you need to safeguard the confidentiality of what you’re about to share. Infidelity happens every day and to tens of millions of people, and needs to be discussed openly. However, you do not want your raw, angry thoughts and statements made in the heat of the moment broadcasted to a wider audience. That kind of dialogue will not help anyone, in my opinion. Your tale of woe may make for great gossip in your community, but how can that be helpful in the long run? Similarly, creating a negative media campaign against your spouse will further polarize you, and is likely to backfire. Divorce your spouse if you want, but creating a battlefield with opposing troops cannot help you, your relationship, or your children.


You write that even for the best of parents, it’s hard to keep their feelings from their children. Could you explain that some more?

Betrayed spouses are angry and traumatized. They often seek revenge. They may unconsciously and unknowingly involve their children in seeking revenge. You may feel that the child should know immediately that this was bad behavior and your spouse is not to be trusted. Perhaps that’s true, but you’ll have a lifetime to speak to them about it. Once you let the cat out of the bag, however, I promise that your children will never forget your words. It’s the norm, I’m sorry to say, for even the best-intended and most altruistic parents to say hurtful things. Be careful.


How long will it take to recover from an affair?

In cases where a spouse having an affair for the first time is contrite, honestly answers all questions, makes a heartfelt and sincere amends, and abandons the affair-partner, a speedier resolution is possible. If the aggrieved partner is open to reconciliation and forgiveness after a due diligence period, that’s a good sign. But there is no telling on how long a wronged spouse will take to heal. There is no statute of limitations on their hurt and anger.


After an affair is discovered, when can we start having sex again?

After infidelity is discovered, I advise a period of abstinence—from a few days to no more than a few months—to create the opportunity for reflection and intention-setting, self- and relationship-improvement, and the chance to live a healthier life with integrity. It is during the period of abstinence, however long or short, that the emotional healing is discussed.


Could you give some sex tips for restarting sex?

Basic sex techniques, taken from the medical discipline of sex therapy, can help couples reach a more comfortable sexual space. The first, simple technique, called Sensate Focus I, couples share a whole-body massage without genital contact. This touch re-establishes some trust and creates some excitement for the future without the pressure of sexual contact. In the second step, Sensate Focus II, couples share a whole-body massage that includes each other’s genitals. When you’re ready, the third step, sex, should be about sharing and joy.


You’re a psychiatrist. Do you ever give medicine to help couples get back into the sack?

Sometimes, sex with a long-term partner is a challenge because you just don’t get that excited. No question about it, this is a psychological problem that you need to talk through. But meds can help too. In all likelihood, during an affair, a female philanderer got incredibly lubricated and the male philanderer got rock-hard erections. Now that you’re with your long-term partner, you may not only miss that rush of having a “new rat in your cage,” but you may also feel nervous about sex. These feelings can also inhibit lubrication and erection. In these cases, a drug like Viagra can be useful. Viagra only improves the plumbing, however.


Aside from Viagra, is there a role for other medications for recovering from infidelity?

If the problem is that one partner has a generally low desire for sex, other meds may be helpful. Medications that increase the brain neurotransmitter of desire, dopamine—like Wellbutrin, Filbanserin, and Buspar—may increase sexual desire. A specialist may even prescribe hormonal treatments in pill form like testosterone to increase desire and arousal in both men and women if naturally occurring testosterone levels are documented to be low on blood tests and when there are no risk factors that contraindicate hormonal treatments, such as cancer. If the problem is the reverse, meaning a person is over-sexed or even addicted to sex and that results in the desire to cheat, other medications can help. There are many medicines that can be taken for this kind of problem. People with sexual compulsivity who need their sexual desires decreased, can take Prozac, Zoloft, or Lexapro, to name a few. At the same time, these meds reduce anxiety and depression. The choice of which medications are prescribed for sexual impulsivity is based on the other co-occurring symptoms associated with the acting out.


Are there other mental health disorders that require medication which may be the source of the problem of infidelity?

Many people commit infidelity out of boredom. A small fraction of these bored people have Attention Deficit Disorders, which we’ve discussed earlier as a problem of needing super-intense stimulation to feel engaged. For them, non-addictive ADD medications may change their lives for the better and may even lead them to be less sexually impulsive.  Even if you opt for a medicinal boost to your sex life, sex begins and ends in your mind. Therefore, by working on your thoughts, emotional intimacy, and talking to your partner, you stand the best chance of making your sex life sexier.