I can’t make a diagnosis on the basis of what you told me. I’d need to know a lot more. I don’t think you have bi-polar illness because you only behave this way at certain times and only with your boyfriend. And I don’t think you have a general anger management problem for the same reason. You don’t report doing these things when you are angry during the day.
I wonder if there is something about going to bed together that makes you terribly anxious. Is it possible that you feel guilty about having sex? Is bedtime a time when you get very close? If so, maybe you get scared about whether you mean as much to him as he does to you. Is it possible that you are testing him to see if he stays even when you lose it? These are the kinds of questions I’d start to explore with you if you came to see me.
I would also ask you how your boyfriend responds when you get out of control. Does he comfort you and plead with you or does he ignore you at this point? If he says lots of comforting things, maybe you have learned to act this way to get his loving attention.
If any of these suggestions ring a bell with you, perhaps you can talk with him about it. If that doesn’t help, I would suggest you see a counselor. A skilled therapist will be able to help you figure out what you are up to and find better ways to get whatever it is you want and need in a more direct and less distressing way.
I wish you well,