This is where being a canon whore is problematic, because 'would have' never really registers with me. That's not to say that it isn't fun reading AU fics where things go wildly different, but because Xander was straight on the show, I just can't picture him any other way.

Not sure that he falls for women he can't have (except in the case of Willow) - he falls for Buffy first time he sees her pretty much, when she's just 'the new girl' and keeps trying for a good while. The Faith sex was obviously... odd, but considering how much fun he went on to have with Anya I can't see that he was put off sex with women! ;)