Wow, congratulations on having your own brain! You clearly know the game here. I think you'll know what to do when you see what he does. You may or may not understand the hell he's going through now, but if he comes out of it on your side, keep him. I say this as somebody who had her husband hang in there for her while she went through roughly the same thing. To be honest I don't know how he did it, because it cost him three years of pain.
Anyway... work out what you want and how much you want to pay for it, and stick with that deal you make yourself. The good stuff in life does cost a lot, and it's worth it. Are you getting a good deal with him? Just be honest with yourself, and you'll be know what to do.