The truth is that, although I don't care much what people do in private, I could never marry a woman who's had casual sex. I find it pretty unadmirable, and wouldn't want a person who behaved that way having and raising my children. Sex and the City makes me want to throw up. So it would be utterly wrong and hypocritical to hold myself to a different standard... and extremely counterproductive, since it would make me unmarriageable from the perspective of a woman who shares my values.