We would all like to believe that affairs are the refuge of the discontented, that only people in unhappy marriages cheat. But “happy,” it turns out, is not a sufficient antidote to affair.

We may be in a golden age of marriage, when elites at least are more likely to report that their marriages are “very happy” than ever before. But the tight, companionable, totally merged nature of the modern marriage is one of the factors pushing people in happy marriages to have affairs, according to therapist Esther Perel. In a recent New York Times profile, Perel is described as the nation’s “sexual healer,” an updated Dr. Ruth. She is the author of Mating in Captivity, which argues that in seeking total comfort, the modern marriage might be squashing novelty and adventure, which are so critical for a sexual charge. She is now working on a new book, provisionally called Affairs in the Age of Transparency, which she considers a sequel, a picture of what the stifling marriage might lead to.

I recently met with Perel in the downtown New York apartment she shares with her husband and two sons. In person, the only thing she has in common with Dr. Ruth is a strong accent, which in Perel’s case is a combination of French and Israeli. She was raised in Antwerp, Belgium, and has lived all over the world, which leads her to regard many American assumptions about affairs to be priggish and provincial. These days, Perel accepts only patients who are involved in affairs, and the vast majority of them, she says, are “content” in their marriages. In fact in surveys that ask adulterers whether they want to leave their marriages, the majority say no. Her book, still very much a work in progress, will be about “people who love each other and are having affairs,” she says, and what that paradox says about the rest of our marriages.

Slate: What do you mean by the age of transparency?

Perel: Transparency is the whole culture. The way a regular person tells everything about themselves on television. The way technology allows us to find out anything—99 percent of the people I see, their affairs are discovered through email or phones. But transparency is also our organizing principle of closeness these days. I will tell you everything, and if I don’t tell you it means I don’t trust you or I have a secret. It doesn’t mean I choose to keep certain things to myself because they are private. Privacy is the endangered species in between two extremes of secrecy and transparency.

Slate: Isn’t the closeness between partners good? Wouldn’t it lead to fewer affairs?

Perel: We have this idea that our partner is our best friend, that there is one person who will fulfill all our needs, which is really an extraordinary idea! So by definition, people must transgress because something is missing at home. We think, if you had what you needed at home, you wouldn’t want to go anywhere else, instead of thinking that marriage is at best an imperfect arrangement.

Slate: It isn’t true that people transgress because something is actually missing?

Perel: We don’t know the exact numbers because people lie about sex and 10 times more about adultery. But the vast majority of people we come into contact with in our offices are content in their marriages. They are longtime monogamists who one day cross a line into a place they never thought they would go. They remain monogamous in their beliefs, but they experience a chasm between their behavior and their beliefs. And what I am going to really investigate in depth is why people are sometimes willing to lose everything, for a glimmer of what?

Slate: And what’s your best guess from your research so far?

Perel: I can tell you right away the most important sentence in the book, because I’ve lectured all over the world and this is the thing I say that turns heads most often: Very often we don’t go elsewhere because we are looking for another person. We go elsewhere because we are looking for another self. It isn’t so much that we want to leave the person we are with as we want to leave the person we have become.

Slate: Is this motivation for an affair particular to our age?

Perel: What’s changed is, monogamy used to be one person for life. If I needed to marry you to have sex for the first time and I knew this is it for the rest of my life, then infidelity becomes one of the ways to deal with those limited choices. But now we come to our marriages with a profoundly different set of experiences and expectations. So the interesting question is, why did infidelity continue to rise even when divorce became available and accepted and nonstigmatized? You would think an unhappy person would leave. So by definition they must not be that unhappy. They are in that wonderful ambivalent state, too good to leave, too bad to stay.

Slate: So what are people looking for?

Perel: What’s changed is, we expect a lot more from our relationships. We expect to be happy. We brought happiness down from the afterlife, first to be an option and then a mandate. So we don’t divorce—or have affairs—because we are unhappy but because we could be happier. And all that is part of the feminist deliberation. I deserve this, I am entitled to this, I can have this! It allows people to finally pursue a desire to feel alive.

Slate: Alive?

Perel: That’s the one word I hear, worldwide—alive! That’s why an affair is such an erotic experience. It’s not about sex, it’s about desire, about attention, about reconnecting with parts of oneself you lost or you never knew existed. It’s about longing and loss. But the American discourse is framed entirely around betrayal and trauma.

Slate: What prevents people from feeling alive in a marriage?

Perel: Marriages are so much more merged, and affairs become a venue for differentiation, a pathway to autonomy. Women will often say: This is the one thing I know I am not doing for anyone else. I am not taking care of anyone, this is for me. And I have a harder time doing that in the context of marriage because I have become the mother who needs to protect the child 24/7 from every little boo-boo and scratch, and I am constantly other-directed so much so that I am utterly disconnected from my erotic self and my partner is longing for sex and I can’t even think about it anymore. And then suddenly I meet somebody and discover something in my body I haven’t experienced for the last eight years, or I didn’t even know existed inside of me.

Slate: So why is the reality of affairs, and the way we talk about affairs, so different?

Perel: In America, the primary discussion of affairs is about the impact of affairs, rarely about the meaning and motives of the affair. If you read 90 articles about affairs, they are all about what’s wrong with you or your marriage—early trauma, narcissism, addictive personality—injuries of all sorts. But there is very little in the general culture that probes the story of the affair—the plot. Just, did you sleep with anyone else? And you can’t glean anything from that. And then the other discussion is about the victim perpetrator model. We need to give the victim ample compassion and the perpetrator needs to feel remorse and repair.

Slate: Do most therapists understand this about affairs?

Perel: Therapists are the worst! They too think something must be wrong for a person to have an affair. Also most therapists in America will not work with secrets. Their attitude is, don’t tell me anything I can’t speak about with your partner. Either you end it or you tell your partner. So half of the time, people lie to the therapist and to the partner. And is it always the best thing to tell? Or can we examine that, rather than live with a blanket policy of which the therapist doesn’t have to live with the consequences.

Slate: So the cheating partner shouldn’t tell?

Perel: In America, lying can never be an act of caring. We find it hard to accept that lying would be protective, this is an unexamined idea. In some countries, not telling, or a certain opaqueness, is an act of respect. Also, maybe the opposite of transparency isn’t intimacy, it’s aggression. People sometimes tell for their own good, as an act of aggression.

Slate: Is it different for women?

Perel: Because it was so fraught, women used to need a really good reason to take that risk. But today, female infidelity is the biggest challenge to the male-dominated status quo.

Slate: Do people see you as condoning cheating?

Perel: I make a distinction between cheating and non-monogamy. Cheating is about a violation of a contract. People misunderstand me because they think I’m saying affairs are OK. No! But I do think examining monogamy is our next frontier.

Slate: You mean as in Dan Savage’s idea that marriages should be non-monogamous? I can’t really see it working for heterosexual couples.

Perel: Not yet, but we couldn’t see premarital sex once either. We are a generation that believes in self-fulfillment, but also in commitment, and in their negotiations between these two ideas they will come up with new negotiations around monogamy.

Slate: Your really believe that?

Perel: Yes. It doesn’t mean it will fit everybody. But I do believe it’s the next frontier.

Slate: Will future arrangements look something like the Underwood marriage onHouse of Cards, where their non-monogamous arrangement is understood between them without being explicitly discussed?

Perel: The Underwoods are totally seen as a power couple. People do not see that they have a profound sense of intimacy. But their intimacy is about how each one supports the other in their own pursuits. So it’s an intimacy based on nurturing differentiation. We are there for each other, to help each of us be who we want to be. And one of the important axes in any relationship is how the couple negotiate togetherness and separateness. The ability to be myself in your presence versus having to let go of parts of myself to be together.

Slate: Do young people enter marriages with different assumptions now?

Perel: When I entered marriage I bought into the whole romantic package. I want my husband to take care of everything. I want to never feel anxious again, never feel a fear of abandonment. It’s the complete merge model. But that’s very different than the millennials I work with. Their fear is that they will lose themselves, because they’ve worked so hard to develop their own identities.

Slate: So it’s a good thing that we are moving away from the merge model?

Perel: But they have the opposite challenge, which is not to be immediately in the zone of fear when they need to get close, when they need to build something together with someone. That’s the price they pay for the highly individualistic culture in which they live.

Slate: What would you say to people who want to preserve a marriage?

Perel: Most people today, for the sheer length we live together, have two or three marriages in their adult life, and some of us do it with the same person. For me, this is my fourth marriage with my husband and we have completely reorganized the structure of the relationship, the flavor, the complementarity.

Slate: Explicitly, or it just happened organically?

Perel: Both. It became clear that we could either go into crisis mode and end it or go into crisis mode and renew. And that is one of the most hopeful sentences a betrayed partner can hear when they come into my office the day after they find out and they are in a state of utter shock and collapse: I say, your first marriage may be over, and in fact I believe that affairs are often a powerful alarm system for a structure that needs change. And then people say: But did it have to happen like that? And I say: I have rarely seen anything as powerful lead to a regenerative experience. This is a controversial idea, but betrayal is sometimes a regenerative act. It’s a way of saying no to a rotten system in need of change.

Slate: Would you ever recommend an affair?

Perel: No more than I would recommend cancer and yet a lot of people finally understand the value of life when they get sick.

This interview has been condensed and edited.