how many people do you know that stay for their entire lives with the first person they have sex with?

how else would you define "monogamy" in a meaningful way?

the truth is that people aren't monogamous and either way, your inability to understand it is far more telling--

you seem to think sex is entirely what men seek. not even men think that. if women prefer monogamy and men prefer as many partners as possible, how is it that you think the men will win and the women lose? if there are no women to have sex with the men, they're not going to get anything.

the "monogamy" you speak of is a compromise.