Are you sure his intent was to make you feel ashamed or disgusting in front of him so he could get through to you that you're accepted by him? You're not disgusting, period, end of statement. There's nothing disgusting or shaming (who would deliberately shame themselves?) about cuts on your arm (or any other part of your body). They're just cuts. It's a bit like the nineteenth century dudes deciding women's legs were sexy and disgusting; everyone has legs, they're just legs, kind of like arms, noses or ears? You cut yourself, it's a symptom/way of coping. Why is that different from someone who talks too much when they're anxious or someone with DID who switches alters?

I think his intent was to make you acceptible to yourself! You are cutting you and that's okay if that's what you want to do. But, is it what you want to do? How do you feel about yourself and taking responsibility for you rather than how he feels about you; he doesn't have to live with you (unfortunately :-) you do.