You never know your partner as well as you think.

I say no to a double standard that men can roam and women must stay put at home. I say no to the fact that men are allowed to claim their sexuality and women just have to pretend that it doesn't matter to them. It's resisting poor relational arrangements. An affair is a way of saying, "No. I'm not playing by the rules." And sometimes betrayal is part of that because you deceive somebody else but you feel like you are, for the first time, being honest with yourself. Sometimes when people have affairs, they feel like they have been lying to themselves for years.

If a woman isn't feeling sexual with herself, she won't respond to advances from any partner, male or female. When this woman goes dancing, she's finding a connection with her own erotic self. It might be about being on a dance floor, feeling free, not having to feel at all responsible for anybody else's well-being. For other people, it might be about going on a hike for four days by herself and reconnecting with nature and strength and endurance and beauty.

In dating, if you say no, your lover goes on to the next person. In marriage, if you say no, the person stays.

The vast majority of unfaithful people are experiencing a conflict between their values and their behavior, and that is the mess of infidelity. It's not an either-or. The idea that you would ask, "How can you say you love your husband and you want to stay married, and you also are having an affair?" Because we are not the same woman, or the same man. Because sexual revolutions don't take place at home. Because for most of us, freedom wasn't something that we experienced in our family, but usually outside of our family.

At this point, we are living one of the greatest experiments in humankind - to create something that has, throughout history, been considered a contradiction in terms - a passionate marriage. Passion has always existed, but it took place somewhere else. Everything that we wanted from a traditional marriage - companionship, family, children, economic support, a best friend, a passionate lover, a trusted confidante, an intellectual equal - we are asking from one person what an entire village once provided. And couples are crumbling under the weight of so much expectation.

For some people, a one-night stand doesn't make any difference in a seven-year love affair. I don't believe the degree of betrayal is always commensurate with the egregiousness of the behavior. They are two separate things.