I agree with this. It sounds like you don't know how to like yourself and you are putting yourself in a position for someone to want you, even if you have to put up with horrible things happening to you. From my experience BDSM is about trust in your partner. To push you to the edge but be in control. That you both are willing participants exploring each other and getting pleasure from the experience. To explore what your limit is. There is pain, but it feels good in a way. It is a consensual expierence of pain, love, trust and sex all rolled into one thing.

It sounds like the guy is guy is to plainly put it, is beating and raping you for his own pleasure. I don't think anyone would feel good after going through that. I could also see how this behavior would feed the self-hatred and self-harming as well. For someone who used to self harm in the past, I could see the things that would push me to be in that position, but it wouldn't be healthy. I think you should stick with therapy. If your current one doesn't help, look for someone who deals with self harm, risk taking behavior and esteem issues. It sounds like there is a part of you that wants a normal healthy relationship, and to be loved, cared for and admired.