My boyfriend insults me when he's angry. Badly.

It's happened around four or five times now but whenever we argue he calls me something really spiteful that he knows will hurt. Then he tried to apologise and says he didn't mean it. He's called me abusive (I've had extensive conversations about this with friends, a therapist, and later my boyfriend after he realised what he'd called me - I'm not), heartless, he's said I'm turning into my father (who has basically been very shitty and uncaring and I think that's all I need to say about him. I've always tried to be the opposite of him. If anything I probably care too much.) and today he called me a cripple. I do have a physical disability that means walking is tiring and I often suffer from chronic pain and I have a limp. I'm sick of being hurt by him but these occasions are rare and often occur because he simply isn't thinking properly and has overreacted or reacted without thought. I just don't know what to do. I love him and what I know he can be, but I need to either get help with growing thicker skin (but I'm worried this will mean I'll care less, and that's the last thing I want), or I need to help him somehow. Please, I'm at my wits end here. I need any advice on how to work on this problem.