Why do we cheat? And why do happy people cheat? And when we say "infidelity," what exactly do we mean? Is it a hookup, a love story, paid sex, a chat room, a massage with a happy ending? Why do we think that men cheat out of boredom and fear of intimacy, but women cheat out of loneliness and hunger for intimacy? And is an affair always the end of a relationship? For the past 10 years, I have traveled the globe and worked extensively with hundreds of couples who have been shattered by infidelity. There is one simple act of transgression that can rob a couple of their relationship, their happiness and their very identity: an affair. And yet, this extremely common act is so poorly understood. So this talk is for anyone who has ever loved. Adultery has existed since marriage was invented, and so, too, the taboo against it. In fact, infidelity has a tenacity that marriage can only envy, so much so, that this is the only commandment that is repeated twice in the Bible: once for doing it, and once just for thinking about it. (Laughter) So how do we reconcile what is universally forbidden, yet universally practiced? Now, throughout history, men practically had a license to cheat with little consequence, and supported by a host of biological and evolutionary theories that justified their need to roam, so the double standard is as old as adultery itself. But who knows what's really going on under the sheets there, right? Because when it comes to sex, the pressure for men is to boast and to exaggerate, but the pressure for women is to hide, minimize and deny, which isn't surprising when you consider that there are still nine countries where women can be killed for straying. Now, monogamy used to be one person for life. Today, monogamy is one person at a time. (Laughter) (Applause) I mean, many of you probably have said, "I am monogamous in all my relationships." (Laughter) We used to marry, and had sex for the first time. But now we marry, and we stop having sex with others. The fact is that monogamy had nothing to do with love. Men relied on women's fidelity in order to know whose children these are, and who gets the cows when I die. Now, everyone wants to know what percentage of people cheat. I've been asked that question since I arrived at this conference. (Laughter) It applies to you. But the definition of infidelity keeps on expanding: sexting, watching porn, staying secretly active on dating apps. So because there is no universally agreed-upon definition of what even constitutes an infidelity, estimates vary widely, from 26 percent to 75 percent. But on top of it, we are walking contradictions. So 95 percent of us will say that it is terribly wrong for our partner to lie about having an affair, but just about the same amount of us will say that that's exactly what we would do if we were having one. (Laughter) Now, I like this definition of an affair -- it brings together the three key elements: a secretive relationship, which is the core structure of an affair; an emotional connection to one degree or another; and a sexual alchemy. And alchemy is the key word here, because the erotic frisson is such that the kiss that you only imagine giving, can be as powerful and as enchanting as hours of actual lovemaking. As Marcel Proust said, it's our imagination that is responsible for love, not the other person. So it's never been easier to cheat, and it's never been more difficult to keep a secret. And never has infidelity exacted such a psychological toll. When marriage was an economic enterprise, infidelity threatened our economic security. But now that marriage is a romantic arrangement, infidelity threatens our emotional security. Ironically, we used to turn to adultery -- that was the space where we sought pure love. But now that we seek love in marriage, adultery destroys it. Now, there are three ways that I think infidelity hurts differently today. We have a romantic ideal in which we turn to one person to fulfill an endless list of needs: to be my greatest lover, my best friend, the best parent, my trusted confidant, my emotional companion, my intellectual equal. And I am it: I'm chosen, I'm unique, I'm indispensable, I'm irreplaceable, I'm the one. And infidelity tells me I'm not. It is the ultimate betrayal. Infidelity shatters the grand ambition of love. But if throughout history, infidelity has always been painful, today it is often traumatic, because it threatens our sense of self. So my patient Fernando, he's plagued. He goes on: "I thought I knew my life. I thought I knew who you were, who we were as a couple, who I was. Now, I question everything." Infidelity -- a violation of trust, a crisis of identity. "Can I ever trust you again?" he asks. "Can I ever trust anyone again?" And this is also what my patient Heather is telling me, when she's talking to me about her story with Nick. Married, two kids. Nick just left on a business trip, and Heather is playing on his iPad with the boys, when she sees a message appear on the screen: "Can't wait to see you." Strange, she thinks, we just saw each other. And then another message: "Can't wait to hold you in my arms." And Heather realizes these are not for her. She also tells me that her father had affairs, but her mother, she found one little receipt in the pocket, and a little bit of lipstick on the collar. Heather, she goes digging, and she finds hundreds of messages, and photos exchanged and desires expressed. The vivid details of Nick's two-year affair unfold in front of her in real time, And it made me think: Affairs in the digital age are death by a thousand cuts. But then we have another paradox that we're dealing with these days. Because of this romantic ideal, we are relying on our partner's fidelity with a unique fervor. But we also have never been more inclined to stray, and not because we have new desires today, but because we live in an era where we feel that we are entitled to pursue our desires, because this is the culture where I deserve to be happy. And if we used to divorce because we were unhappy, today we divorce because we could be happier. And if divorce carried all the shame, today, choosing to stay when you can leave is the new shame. So Heather, she can't talk to her friends because she's afraid that they will judge her for still loving Nick, and everywhere she turns, she gets the same advice: Leave him. Throw the dog on the curb. And if the situation were reversed, Nick would be in the same situation. Staying is the new shame. So if we can divorce, why do we still have affairs? Now, the typical assumption is that if someone cheats, either there's something wrong in your relationship or wrong with you. But millions of people can't all be pathological. The logic goes like this: If you have everything you need at home, then there is no need to go looking elsewhere, assuming that there is such a thing as a perfect marriage that will inoculate us against wanderlust. But what if passion has a finite shelf life? What if there are things that even a good relationship can never provide? If even happy people cheat, what is it about? The vast majority of people that I actually work with are not at all chronic philanderers. They are often people who are deeply monogamous in their beliefs, and at least for their partner. But they find themselves in a conflict between their values and their behavior. They often are people who have actually been faithful for decades, but one day they cross a line that they never thought they would cross, and at the risk of losing everything. But for a glimmer of what? Affairs are an act of betrayal, and they are also an expression of longing and loss. At the heart of an affair, you will often find a longing and a yearning for an emotional connection, for novelty, for freedom, for autonomy, for sexual intensity, a wish to recapture lost parts of ourselves or an attempt to bring back vitality in the face of loss and tragedy. I'm thinking about another patient of mine, Priya, who is blissfully married, loves her husband, and would never want to hurt the man. But she also tells me that she's always done what was expected of her: good girl, good wife, good mother, taking care of her immigrant parents. Priya, she fell for the arborist who removed the tree from her yard after Hurricane Sandy. And with his truck and his tattoos, he's quite the opposite of her. But at 47, Priya's affair is about the adolescence that she never had. And her story highlights for me that when we seek the gaze of another, it isn't always our partner that we are turning away from, but the person that we have ourselves become. And it isn't so much that we're looking for another person, as much as we are looking for another self. Now, all over the world, there is one word that people who have affairs always tell me. They feel alive. And they often will tell me stories of recent losses -- of a parent who died, and a friend that went too soon, and bad news at the doctor. Death and mortality often live in the shadow of an affair, because they raise these questions. Is this it? Is there more? Am I going on for another 25 years like this? Will I ever feel that thing again? And it has led me to think that perhaps these questions are the ones that propel people to cross the line, and that some affairs are an attempt to beat back deadness, in an antidote to death. And contrary to what you may think, affairs are way less about sex, and a lot more about desire: desire for attention, desire to feel special, desire to feel important. And the very structure of an affair, the fact that you can never have your lover, keeps you wanting. That in itself is a desire machine, because the incompleteness, the ambiguity, keeps you wanting that which you can't have. Now some of you probably think that affairs don't happen in open relationships, but they do. First of all, the conversation about monogamy is not the same as the conversation about infidelity. But the fact is that it seems that even when we have the freedom to have other sexual partners, we still seem to be lured by the power of the forbidden, that if we do that which we are not supposed to do, then we feel like we are really doing what we want to. And I've also told quite a few of my patients that if they could bring into their relationships one tenth of the boldness, the imagination and the verve that they put into their affairs, they probably would never need to see me. (Laughter) So how do we heal from an affair? Desire runs deep. Betrayal runs deep. But it can be healed. And some affairs are death knells for relationships that were already dying on the vine. But others will jolt us into new possibilities. The fact is, the majority of couples who have experienced affairs stay together. But some of them will merely survive, and others will actually be able to turn a crisis into an opportunity. They'll be able to turn this into a generative experience. And I'm actually thinking even more so for the deceived partner, who will often say, "You think I didn't want more? But I'm not the one who did it." But now that the affair is exposed, they, too, get to claim more, and they no longer have to uphold the status quo that may not have been working for them that well, either. I've noticed that a lot of couples, in the immediate aftermath of an affair, because of this new disorder that may actually lead to a new order, will have depths of conversations with honesty and openness that they haven't had in decades. And, partners who were sexually indifferent find themselves suddenly so lustfully voracious, they don't know where it's coming from. Something about the fear of loss will rekindle desire, and make way for an entirely new kind of truth. So when an affair is exposed, what are some of the specific things that couples can do? We know from trauma that healing begins when the perpetrator acknowledges their wrongdoing. So for the partner who had the affair, for Nick, one thing is to end the affair, but the other is the essential, important act of expressing guilt and remorse for hurting his wife. But the truth is that I have noticed that quite a lot of people who have affairs may feel terribly guilty for hurting their partner, but they don't feel guilty for the experience of the affair itself. And that distinction is important. And Nick, he needs to hold vigil for the relationship. He needs to become, for a while, the protector of the boundaries. It's his responsibility to bring it up, because if he thinks about it, he can relieve Heather from the obsession, and from having to make sure that the affair isn't forgotten, and that in itself begins to restore trust. But for Heather, or deceived partners, it is essential to do things that bring back a sense of self-worth, to surround oneself with love and with friends and activities that give back joy and meaning and identity. But even more important, is to curb the curiosity to mine for the sordid details -- Where were you? Where did you do it? How often? Is she better than me in bed? -- questions that only inflict more pain, and keep you awake at night. And instead, switch to what I call the investigative questions, the ones that mine the meaning and the motives -- What did this affair mean for you? What were you able to express or experience there that you could no longer do with me? What was it like for you when you came home? What is it about us that you value? Are you pleased this is over? Every affair will redefine a relationship, and every couple will determine what the legacy of the affair will be. But affairs are here to stay, and they're not going away. And the dilemmas of love and desire, they don't yield just simple answers of black and white and good and bad, and victim and perpetrator. Betrayal in a relationship comes in many forms. There are many ways that we betray our partner: with contempt, with neglect, with indifference, with violence. Sexual betrayal is only one way to hurt a partner. In other words, the victim of an affair is not always the victim of the marriage. Now, you've listened to me, and I know what you're thinking: She has a French accent, she must be pro-affair. (Laughter) So, you're wrong. I am not French. (Laughter) (Applause) And I'm not pro-affair. But because I think that good can come out of an affair, I have often been asked this very strange question: Would I ever recommend it? Now, I would no more recommend you have an affair than I would recommend you have cancer, and yet we know that people who have been ill often talk about how their illness has yielded them a new perspective. The main question that I've been asked since I arrived at this conference when I said I would talk about infidelity is, for or against? I said, "Yes." (Laughter) I look at affairs from a dual perspective: hurt and betrayal on one side, growth and self-discovery on the other -- what it did to you, and what it meant for me. And so when a couple comes to me in the aftermath of an affair that has been revealed, I will often tell them this: Today in the West, most of us are going to have two or three relationships or marriages, and some of us are going to do it with the same person. Your first marriage is over. Would you like to create a second one together? Thank you. (Applause)