I don't know what to tell you. I was in a very similar situation, and even though I really tried, it didn't end well. If you can't even talk to your partner about your feelings, thoughts, and concerns without him blowing up...well, that's a fundamental part of maintaining a relationship.

I had a previous partner who most likely had bipolar with some BPD traits (therapists had input on this as well), but she believed she could manage it with vitamins. She didn't want to do any focused therapy on those issues, get an assessment, try any medication, or work with me. From her perspective, everything wrong with our relationship was all my problem and I just had to try harder (which was pretty ironic when I was the one going to regular therapy sessions and reading all the self-help books). Being with her was extremely stressful and definitely exacerbated my issues. If someone refuses to see their part in the problems and take action on that, then you're pretty much done, even if the curtains haven't come down quite yet.

I hope this works out for you somehow. But in my experience, people rarely change in such things. If he has been so determined not to work on this, it will likely continue in that fashion.