My husbands anger and ADD

So I'm new to all of this, my husband was diagonis with ADD about 4 years ago. We've been married for two years and it seems just to be getting worse. Kinda like a roller-coster. One minute he's happy and telling me how much he loves me and our son and the next he is wanting a divorce because he is convinced he doesnt make me happy! Ive tried to understand where he is coming from and trying to talk to him but he is always on the defense. He wont help me around the house but there are times when I ask him and he is fine. I dont understand how to talk to him about things that are important without him shutting down on me. We are currently going through a bankruptcy because he can't pay bills on time and has out of control spending habits. Can someone please help me understand what I can do, because Im exhausted and it feels like Im the only one in my marriage when he gets at his low points. I just got him to agree to see someone but its like pulling teeth.