My personal take on this... is that no one deserves to be abused, and what he's doing to you is verbal abuse. No matter WHAT is going on in someone's life, it doesn't give them the right to be abusive.

Sure, sometimes it might happen where someone just explodes from all the stress..... but that would be a one-time occurance. From what you said, it sounds like this is a regular enough ordeal that you've already left him once.

I am proud of you for being SO supportive, but he needs to either get himself in check or you need to check out. Does he know anything about verbal abuse? If you aren't sure... I'd try printing him off something from a website that explains what verbal abuse is. He'll likely get mad, but after a day or two if he doesn't see that it's what he is doing and/or isn't willing to make changes in how he expresses himself.... then why on earth would you stay around?

I hope that he will start changing his behaviour so that you can both be happy, he needs your support and you clearly care very much about him! If only he appreciated your love and support.... does he show you how much he appreciates you at all?