Why are powerful men so likely to cheat on their wives?

Rabbi Shmuley Boteach, on Huffington Post, argues:

The biggest mistake we make in determining why powerful men cheat is to believe they're looking for sex. If it's sex they're after they have wives who can cater to their needs. No, these men are looking for something else entirely: validation. Men cheat not out of a sense of entitlement but out of a sense of insecurity. . . .

What makes men slowly climb the ladder of success is a desire to prove they're a somebody. They want to be and feel important. . . . It is not the promise of their potential that drives them, but the fear of being a nonentity. . . .

And that's why these men turn to women to make them feel good about themselves. They want to feel desirable. They seek to silence the inner voices that taunt them as to their own insignificance. Because of its power, sex has a unique capacity to make insecure men feel -- however fleetingly -- like they're special. Having women desire them makes them feel desirable.

Amy Alkon (the "Advice Goddess") says: "Oh, please." Rabbi Boteach "doesn't get it":

They take sex because it's there, in variety, because they can. Because it would be fun to have a little strange, and the little strange is right there bending over sweeping up a broken glass, and seems willing, and Maria is nowhere to be seen. . . .

Regarding the evolved male preference for sexual variety, as the late Margo Wilson and her husband and partner Martin Daly pointed out: Sperm are cheap; eggs are expensive.

I don't see why there needs to be a polarized debate about whether men commit adultery because they want sex. Of course they want sex. But even if Alkon's evolutionary-psychology explanation is right, that alone isn't a reason to dismiss other explanations like Rabbi Boteach's.

Robert Wright explained why in his book The Moral Animal. First, here's his explanation of why men (more than women) become increasingly likely to cheat as they get older and more successful:

As a marriage progresses, the temptation to desert should—in the average case—shift toward the man. The reason isn't, as people sometimes assume, that the Darwinian costs of marital breakup are greater for the woman. True, if she has a young child and her marriage dissolves, that child may suffer—whether because she can't find a husband willing to commit to a woman with another man's child, or because she finds one who neglects or mistreats the child. But, in Darwinian terms, this cost is borne equally by the deserting husband; the child who thus suffers is his child too, after all.

The big difference between men and women comes, rather, on the benefits side of the desertion ledger. What can each partner gain from a breakup in the way of future reproductive payoff? The husband can, in principle, find an eighteen-year-old woman with twenty-five years of reproduction ahead. The wife . . . cannot possibly find a mate who will give her twenty-five years worth of reproductive potential. This difference in outside opportunity is negligible at first, when both husband and wife are young. But as they age, it grows. . . .

A poor, low-status husband may not have a chance to desert and may, indeed, provide his wife with reason to desert, especially if she has no children and can thus find another mate readily. A husband who rises in status and wealth, on the other hand, will thus strengthen his incentive to desert while weakening his wife's. (87)

Now, here's Wright on why the ev-psych explanation isn't mutually exclusive with other psychological explanations:

Objections to this sort of analysis are predictable: "But people leave marriages for emotional reasons. They don't add up the number of their children and pull out their calculators. Men are driven away by dull, nagging wives, or by the profound soul-searching of a mid-life crisis. Women are driven out by abusive or indifferent husbands, or lured away by a sensitive, caring man."

All true. But . . . emotions are just evolution's executioners. Beneath all the thoughts and feelings and temperamental differences that marriage counselors spend their time sensitively assessing are the stratagems of the genes—cold, hard equations composed of simple variables: social status, age of spouse, number of children, their ages, outside opportunities, and so on. Is the wife really duller and more nagging than she was twenty years ago? Possibly, but it's also possible that the husband's tolerance for nagging has dropped now that she's forty-five and has no reproductive future. And the promotion he just got which has already drawn some admiring glances from a young woman at work, hasn't helped. (88)