Actually, most American men want to be monogamous too. The narrative of the randy male, always on the prowl is a myth for a lot of men. Sure, some guys want that, but most don't for the same reasons that most women want just one partner - because there's more to relationships than just sex. Of course, men are interested in sexual variety as well if they can figure out a way to have it and the relationships they want (as perhaps in consensual non-monogamy) but it doesn’t kill their libido in the way it does for women if they have the same kind of routine sex over and over again with the same person.
"Among heterosexuals, the numbers skew slightly towards men having more partners, but overall really aren’t that significantly different, particularly when you take into account how much more women have to consider their safety, whether or not they will get pregnant, and other social considerations that men today don’t have to face, such as being considered a slut. The only place where there is a large difference is at the very highest end of the spectrum. Only 12.9% of women have had 15 or more partners vs. 28.3% of men ages 25–49, but in every other category, it’s pretty similar."
Additionally, most of the men surveyed had, in general, the number of sex partners they wanted to have - so it's not that men have a lot fewer than they truly want. There are lots of cultures where pair bonding takes place, but strict sexual monogamy does not and it has nothing to do with what is "natural" for a particular gender. Among the Aché of Paraguay, women who are past childbearing age have an average of 13 "marriages" - those being formed or dissolved by where you sleep at night.
Relationship dynamics in a patriarchy like the US, where up until 50 years ago women were second class citizens by law and didn't have great opportunities to provide for themselves and so were dependent on one man are very, very different than they are in other cultures where those dynamics are not in play.
