Rage outbursts during happy times? Inappropriate emotional response?

I am having a long term problem with my fiancé. He has severe rage issues, zero tolerance, and needs anger management DESPERATELY. But what is really bothering me is his inappropriate emotional responses. When he should be happy, he will go into rages for absolutely no reason. He will get paranoid and think I gave him a look, or slammed the door, literally anything. Before I know it, it is WW3. He is breaking doors (punching holes THROUGH the doors, clear to the other side) calling me every name in the book- he hates me, i ruined his life, you name it. It always happens when he should be happy. Example- Christmas Eve. Enough said. He denies everything, he had a reason to be upset, but cannot "remember." Also, we are leaving for Florida tomorrow morning, taking a road trip, so he can see his family and his kids which he hasn't seen in a long time. He has been super excited all week, even today. Then, all of a sudden, he bursts into the room where I am packing, and FLIPPED. Apparently "he knows me" and KNOWS I was givin him an attitude from across the house because I slid the laundry basket across the floor. Yes, WW3. I have no idea what is going on with him. It had always been like that, no matter what it is. It seems like when he has happy emotional overload, he explodes. Does anyone know about this or how to stop it? I know he does have some type of mood disorder, but he keeps making excuses as to why he hasn't gone to the dr. He is divorced, and has had this along with many other problems for over 15-20 years. Any suggestions?!? I know I didn't explain it right, but if you guys want other examples or more info, let me know. I can write a book!! Lol