Maybe because you're waiting for the right girl to come along and sweep you off your feet?
Then you're just a shy pervert who hasn't found a girl to stick his díck in yet.
You haven't found the right person. I'm assuming you haven't dated anyone, otherwise you have either confidence issues or a weak relationship if you are in one and have yet to kiss them (unless it's early in the relationship, in which case hang in there).<br />
But if you haven't had a relationship yet, don't worry about it. Someone will come along, and it's better than rushing into a bad one just for the sake of a relationship. Find someone you like, become friends, and ask them out. Or try online dating.
You're probably just shy! (:
Well you're a good looking guy, i'm sure it wont be too much longer! What's the rush?