Re: What to do?
Make that two! I agree completely with Valerie (as usual!). You are not obligated to anyone at 16, regardless of how long you've been seeing eachother, how they feel about you, or what they might do. You do have some sense of obligation to be kind and clear with him, though, after this much time with you he deserves that much.
If you're worried about what he'll do, that is not enough of a reaon to be a prisoner. Tell your folks, let them help you here.