Hey there, I bought a house w/ my AH as well, and I think one of the reasons I put up with his behavior and drinking for so long was because I kept hoping he would eventually come through on his promises and help dig us out of the hole of huge debt he'd been getting us into.
It NEVER happened! I don't believe it will, and even if he could it would be a long shot now. You may have a house with him and that could cause problems but if you are joint on the home and are tennents in common or whatever it is, I believe you can force the sale of the house with a court order-- I may be wrong here.
Everyone is different, but from the sound of your posting it seems like things are pretty bad with him already. There's a lot of good information on the boards about being codependent, and going to Al-Anon and individual therapy has helped a lot of people here, including myself.
The good news is you have plenty of support on boards like these and if you attend group therapy you will find support there as well, because not everyone is lucky enough to have a lot of family or friends to fall back on, particularly after going through things like this.
Good luck!