"In fact one of our most comforting assumptions, soothing perhaps above all to men but clung to by both sexes, that female eros is much better made for monogamy than the male libido, is scarcely more than a fairy tale.
Certainly, women are no better suited for monogamy than men are. That, I think, is clear. It seems possible, if you look at some of the data, that women are even less well-suited for monogamy than men. It’s important to distinguish between the sexual level of desire, and what we choose in our relationships for all kinds of reasons. But on a sexual level, women are even less suited to monogamy.
Partly, I do think that, ironically, has to do with the force of culture. Now that would take us to a really complex part of neuroscience that maybe is best left for another time. I do think that men who’ve been blessed to happily think that it’s only they who are having trouble with monogamy, and that their wives or long-committed girlfriends are more or less just fine with it, they may have a lot to worry about."

Daniel Bergner