How is he making you feel about yourself, you can try and help him if he wants it but I'd look after your own well being first and maybe take a step back, if your in a close relationship with him and he has BPD you could become victim to that behaviour, in my experience it wasn't physical but subtle psychological abuse and it would come in waves, he'd be fine for a while and things would be great but then he would start to stop communicating, do little things like turn the phone off, give one worded replies to everything, just sit there on the edge of the sofa just looking at nothing and you couldn't get anything out of him what was wrong. sex would also be a problem and they would withhold it, I would just think what the hell have I done wrong. For example someone would ring him and his personality would change totally, he would be all happy and outgoing like I wasn't as good as them, like he wasn't trying to rub it in my face, soon as the conversation ended he would go back to how he was before. It was lots of little things, if I mentioned anything he would just give me the silent treatment so I started not to mention anything, I'd live with it and try and hold it in. But then there would be periods and we would get on like a house on fire and I couldn't understand why it couldn't stay like that. I suppose I became the center of his behaviour so I was to close to it to be able to help him because I was being hurt by it.
I dated a man whose behavior was strikingly similar to that of your boyfriend. It turned out that he has BDP or Borderline Personality Disorder. From personal experience and from what I've researched and read, relationships with these individuals is extremely difficult, highly destructive and rarely work out. Might I suggest that you read an excellent book titled: "Stop Walking On Eggshells" by Paul T. Mason and Randi Kreger. It offers interesting insights and helpful suggestions about dealing with the personality that you described. If you decide that you have no choice but to leave the relationship... I recommend that you read another exceptionally helpful book called: "Breaking Free From Boomerang Love" by Lynn Melville.
Physical violence sometimes starts with hitting other things. If he gets angry enough to destroy something over something little then yes eventually he can and may move that anger onto you.
Please get him to an anger management class or a therapist so that he can learn to control his anger and possible figure out why he gets that way to begin with.
He just needs to get in therapy, I don't think there is anything that you can do.