Why is female virginity connected to purity in the Bible but not male virginity?

I have no answers for this question.  I just know that in the Bible, it is an analogy that is made time and time again.  Purity as demonstrated by female virginity.

I want to be frustrated by it.  I want to feel its unfair.  It lends itself to the incorrect views by some men that female virginity becomes a requirement for women, but that men do not have to remain in the same state of purity.  That conclusion certainly isn’t supported by Scripture, yet…

Does anyone have an answer for this?  Maybe I’ll come across something when I do more studies on gender in the next year.  I might even have the opportunity to delve a bit into the topic of sexuality in the Old Testament.  But in the meantime, if you have thoughts, feel free to offer them.