there are just as many women out there sleeping with men as men sleeping with women (oddly enough, the math works like that), so how can any of you say that this is a problem with men? secondly, if there are fewer women having sex than there are men, then the women who are having sex are having LOTS of it to make up for all the women who hold back.
and sal, watch out - if the guy finds out you assumed he was hitting on you when in fact he was only trying to be nice and has no interest in you, he will think you have the biggest ego ever and probably detest you. well, if i was that guy, i would, reminds me of two such incidents, and i found it really hard to get over the egos of those two girls. it was especially easy for me to resent them afterwards, because i had no interest to begin with.
it would have to be pretty obvious to assume such a thing without being conceited at the same time.
and please don't say: "i have a bf" unless the situation merits it. i have a friend who asked his ex gf to coffee, and she said: "i have a bf". well, anyway, my friend may have liked this girl before (NOT at the time), but let me say, she was ugly in all ways, inside and out, and hearing her say that made me lose an awful lot of respect (assuming i had any for her to begin with).
just don't associate with the guys who are assholes, but give them the benefit of the doubt, until you have some kind of reason to stop talking to them. there are a lot of nice PEOPLE out there (both men and women) and there's no need to waste time with the jerks of either sex.