Not all affairs, as much as we would like to think of it like that, are symptoms of troubled marriages. Picture: Pexels

Why do people cheat, and how do couples survive infidelity and come out stronger on the other end? Esther Perel has been studying these questions and others in her work as a couples therapist, writer and podcast host.

Her new book, The State of Affairs, examines infidelity from all points of view - the person who cheated, the person who was cheated on, and the third party - in an attempt to understand how to make modern relationships more resilient. The following interview has been edited for length and clarity.

Q: How is it that people in good, happy relationships end up cheating?

A: It may have nothing to do with their relationship. People come in and tell me, "I love my partner, and I'm having an affair." I spoke with a woman recently who has cancer. Who does she find herself with? The person who is helping her rehabilitate. She says: "I just found myself drawn to this person. I felt alive. I had a vitality with him because he was helping me get better again."

Not all affairs, as much as we would like to think of it like that, are symptoms of troubled marriages. And neither are they symptoms of troubled people. They are expressions of people seeking something.

Q: Why can't people find that vitality with their partner who knows them really well?

A: Because the partner has been with you in the hospital every day; the partner is the one with whom you've been scared; the partner is the one with whom you've been thinking about the potential of dying. The partner has been there to help you in the most incredible way and you can't be in front of that partner and forget all of that so easily. Affairs are utopian stories that live on the sideline of your real life.

Q: Is there a way to harness that feeling within a relationship?

A: One of the most important things in the couple is to actually sort this out. To figure out: How did this thing happen? What does it mean for us? Is there something about it that we could have done differently or that I could have done differently? Or is this completely separate from us? That is very difficult sometimes for people to imagine.

When you have these experiences, it is not about necessarily being with another. It's about you being another. There is no greater other than a different version of yourself.

The State Of Affairs by Esther Perel. Picture: HarperCollins

Often an affair is a galvanizing experience. It's either: Break it or remake it. When you remake it, you have to ask yourself: What are we going to do with this? We're not just going to suffer here. We're going to let this push us to reclaim each other in a better, stronger, more honest way. That's what it means when people come out on the other side, saying: Our relationship is much stronger.

Q: How is it possible for a relationship to be stronger after infidelity?

A: Go back to the metaphor of the illness. Nobody seems to question that when you have a life-threatening illness, it can change your perspective. It can help you reorganize your priorities, realize what you don't want to lose, where you need to show up differently. That doesn't mean that you recommend people to have cancer.

This crisis will sometimes kill the relationship that was already dying on the vine, and people will use it as the opportunity to get out. Or it will jolt people out of a level of complacency, laziness, estrangement, misbehavior that they realize they don't want to lose what they've built.