He is obviously a sexual deviant. Dominance and submissance is fine if both parties enjoy it. The fact that he is forcing this behaviour upon you and threatening you is not a good sign.
Most murderers and serial killers practise this same behaviour with their partners.
If somebody fantasises about violent sex, they feel the need to take it a step further by 'acting' out the fantasises with a partner.
Sooner or later this is not enough and the person needs to do it for real.
I am not suggesting that your boyfriend is a homicidal maniac...But it is possible.
You need to talk to him about his sexual behavior and tell him that it is a turn off or that it makes you feel afraid and threatened.
His reaction should be enough to help you make a decision on whether he is right for you or not.