Well, for one thing, chastity comes more easily to women than it does men. There is plenty of scientific backing for this. Women are wired not to actively desire sex at levels similar to those of men until after they’ve *started *having sex – this is an evolutionary program aimed at ensuring (a) that women will not be ruled by hormones when picking a mate who must care for them and their children, and (b) that, having chosen (wisely, because free of hormonal rule) a suitable spouse, they will come to desire him and thereby have many, many children with him.
I think this explains why some non-virgin women get into the same pattern of really bad relationships – with punks, drug dealers, abusers, etc. Everyone around them, even the women themselves, know these relationships are bad and that they shouldn’t be getting involved in them. But those women’s ability to make rational decisions on the basis of this knowledge is attenuated by their sexual desire for these kinds of men – a desire aroused by the changes to the brain caused by the loss of virginity in the first place. (That’s just a speculation, I have no idea if it has scientific backing.)
At any rate, if chastity comes more easily for women, isn’t the burden of chastity therefore on them? They have less excuse for slipping up, unlike men who are ruled by their sex drive pretty much from puberty. The obvious analogy would be to courage. Men are expected to be courageous because they are physically stronger. A man who resorts to shrieking hysterics when attacked is a coward; a woman who does the same thing is not a coward. That’s because men have less of an excuse for such behavior than women, being, by nature, better equipped to confront dangers and threats.
The corollary of this is that, since it takes two to tango (hah!), if all women did what came naturally to them – which is to say, remain chaste – it follows that all men (who aren’t rapists, at least) would have to be chaste by default. So in that sense, at least, the “double standard” can be understood as rational.
None of this is to say that men shouldn’t exercise sexual self-control. They should, precisely because they can and because it’s good to do so. (And it’s not near so hard as most men say it is. If I can kick sexual self-indulgence cold-turkey, anyone can!) It’s just that men and women differ sexually, and chastity is a virtue relating to sex, so it follows it’s going to have different implications for men and women. If it does, it follows we should recognize and act on those differences accordingly.
Just food for thought!