Okay, my ealier post was crap, so I'll do better.
This question is hard to answer, even when I kind of want to.
In the last year I've started to identify as asexual. Mostly just in my own head. The minute I did so, I started to worry that giving it a name would make me stubborn - I mean, someday I might want sex. If I get all asexual-proud, I might just throw away something I want someday for no reason. In other words; asexuality is a wierd sexual identity for people who don't want to base their self image on what they are not. Like, I'm an athiest, too, but that just means god and religion are not important parts of my life and I don't want to talk about it.
Now and then I casually drop a "Oh yeah I'm asexual" into a conversation, and it almost always is a bad idea, unless I want to spend an afternoon describing the difference between being celibate and asexual(Ey, thanks for being an exception to this,
@EphemeralStick), or explaining that my life is not loveless. God forbid I ever make a dirty joke after that, either!
Anyway, I guess I can't exactly give a good answer to why I don't want to have sex. I should probably bring it up more often, though, if only to get people used to the idea.