Health & Sex

Why We Cheat

continued...

What are not taken into account in these surveys are other kinds of infidelity besides having sex. Does a stolen kiss count? What about erotic chats with strangers online? A lap dance?

"Infidelity occurs when one member of a couple secretly violates the commitment to monogamy. That's a very inclusive definition," Lusterman says. If your partner considers it cheating, then it probably is. But what would mortify your partner might be a-OK, or at least tolerated, by mine.

"I think there probably is a bigger range of fidelity than we imagine," Kramer says. Some couples enjoy bringing third parties into their bedroom, yet they would insist that they have never cheated.

 

Another problem with infidelity statistics is whether to read that the glass is 22% empty or 78% full. Certainly, many, many people cheat. But most people apparently do not, at least by the conventional definition.

Besides the great pressure from religious and cultural mores to stay faithful, and the threat of retribution, there are prizes for fidelity.

"There are more complex types of happiness to be found in behaving in an open and moral way, negotiating whatever problems there are," Kramer says.

Monogamy is "essentially an arms treaty," Lipton says. "Given the ubiquity of sexual jealousy, I will agree not to make my partner crazy with sexual jealousy by foreclosing some of my sexual options, if my partner agrees not to make me crazy by foreclosing his options."

From an evolutionary standpoint, it also has advantages for men. First of all, it ensures that the child you're working so hard to rear is biologically related to you, and secondly, to ensure that you get a mate, if you're an average guy. In social groups that form harems, males at the top of the heap get all the women. "Monogamy equally distributes males and females in the culture, instead of Wilt Chamberlain getting 20,000 women, and somebody else getting zero," Lipton says.

And there are warm, fuzzy reasons. "As I'm growing older and my husband's growing older, and we're monogamous, it's so pleasant to have one other person that you trust completely," Lipton says. "It's a treasure."