<human>: Can you provide a brief rundown of the text in within 3 sentences?

I've been with my BF for over a year now and the relationship has been great overall. He's incredibly smart, funny, and nice, the usual stuff. Our life seems to mix well together though he is a bit different in being more introverted and less traditionally romantic.

He's also really honest and so we started communicating and I learned a lot about him I didn't know. The first thing came from sex, it turns out he's really into bondage, exhibitionism, spanking, and we ended up doing those things because I trusted him. He appreciates it however it turns out he said he's also into stuff like choking and slapping but he was very adamant that he just wanted to tell me and he wouldn't do it if I didn't want it. 

That was the first thing where I didn't really realize he was into or thought those things. The main reason I'm making this post is sometimes he has told me he basically wants to insult/degrade me in a non-sexual or sexual manner, it didn't matter. He's admitted to emotionally abusing one of his exes when he was 19 though she was also emotionally manipulative/cheating on him. I don't know what to say or do in that situation and really, I get scared he will hurt me emotionally. He directly told me that there's a sense of control when you hurt your partner of course and he finds it disgusting yet the feelings come once in a while. I'd like to say this has happened rarely but I only know when he feels this way if he tells me, he's very good at hiding if he feels a certain way if he thinks the time isn't appropriate. 

So other than being scared of it, I asked if he was going to seek help. He said no, most likely not. He's thought about it a lot and he knows why he feels this way and other things. Basically, what I want to know is I don't want to feel like there's this unknown scary part of him forever. Either I want to fully trust him or for him to get help. He has been completely honest and that has helped but since I had no experience in any of this, I don't know what to do. Thanks for any opinions!
<bot>: My BF admitted to having desires of emotionally insulting/degrading me but has never acted upon it yet. Thoughts?