[b]Purple rain[/b] gave you good advice. Let me expound a little on what he or she said.
You may think you love your now ex-bipolar boyfriend, but love is not enough to make a relationship work. There has to be a mutual commitment, shared goals and similar enough values. If one of your goals is marriage and children, do you really want your future kids to have a father who is mentally ill? Is this a disease you want to pass on? I would hope not. And that makes this guy Mr. Wrong.
But that’s the big picture. Closer to home is the fact that your boyfriend breaks up with you “occasionally”. And now he’s accused you of lying when you haven’t. This may be delusion developing as part of his illness. If he doesn’t take care of himself and see his doctor regularly and make sure his medications are correctly prescribed and administered, things can really get super rocky. This isn’t healthy and for you to go along with this for three years means your idea of what a healthy relationship is, is warped. You need to understand that when you get involved with someone who’s mentally ill, you’re asking for all kinds of problems. The mental illness is like a third person in the relationship.
If you really think your boyfriend is going to hurt himself, you need to call the police and tell them. That’s your responsibility.
For now, I think it’s best if you don’t contact him. Since he’s even blocked you from e-mailing him, he’s made it more than clear that he’s done. And I’m sorry you’re hurt, but I think it’s a good time for you to let go and move on.
I hope that helps. Please let me know how things go, and follow me @AskAprilcom on Twitter.