Well, your boyfriend is selfish. And you are an enabler.
See, he tells you he won't do it, so he doesn't. However, you tell him he won't, and he's holding out on sex? What part of the game is that?
Basically, you've given him the green light to have what he wants all the while you end up doing what he wants. Do you see how he keeps winning here? He's like Charlie Sheen!
I hate to say it, but the only way to win in this situation is to stick to your guns and not give him any head if he won't return the favor. And if that means no sex, well so be it. You all will be the state of Wisconsin versus the teacher's unions then. Either he comes to terms with the fact that in order to get you have to give or it might be time for you to roll out. And I mean that. See, this can't be the only place where he's selfish. It's impossible. People who are used to getting their way attempt to do that in every facet of their lives. And when they don't, they pour or act up.
So hold out on sex. It might be hard (no pun intended) but it's the only way. And if you all never get it on again because he won't reciprocate, then he aint the one for you anyway, boo.
just suck his dick