I've genuinely wondered about this question. I know tons of otherwise reasonable dudes who say about a particular girl "she's nice and good looking and all, but she's been with too many guys. It's kind of gross." There are a lot of historical/cultural reasons why a guy wouldn't want to be with woman who sleeps around, but I think we've generally progressed as a society past the point where a woman's virginity was prized as her most valuable asset. It makes absolutely no sense to me that a guy would or wouldn't sleep with a girl based on her history, assuming she doesn't have any STDs or anything. Is it honestly a turnoff to know that tons of other guys have been there before?
Serious answers only please. I'm not looking to judge men or women for their sexual preferences. I'm just curious as to why this seems to be the case.