When someone you love has A&D :(

my partner of 3 years has anxiety,depression,ptsd and possible multiple personality.this post will probably be a huge babble but I'm hoping someone will take the time to read and maybe able to somewhat advise me on how to better deal with things. So.. I met my partner who was then a hard working loving man just over 3 years ago. He was working as an engineer. He explained he had only recently split from his ex partner who he had 2 children with. Since informing his ex of his new situation she has pretty much made his life hell, from being refused access to kids, to damaging his property, setting him up to be arrested and spreading rumours making it look like she is a victim! Since all of this he has come out of work and slowly he has detoriated into this mess on the sofa playing computer games for upto 12 hours a day! His personal hygiene is pretty non existent unless I nag at him to. He doesn't help at all with housework and I work too.Whenever I try to talk to him about this situation he goes into a rage and becomes the most Nasty person I've ever seen. Comments that stick. "I make him sick" "he doesn't want to be with me " I'm a slag etc. This weekend things took a turn. I had a night out planned which he was made well aware about weeks in advance. On the day of me going he accused me of lying about who I'm going out with and me taking drugs! (Something I don't do btw) and others about me being a slag for wanting to go out. Thing is his issue is that we had argued recently and many of these comments was mentioned and he has spent all week winding himself up and getting anxious that I would go out and cheat in retaliation to his nasty comments. I still went out and came home as promised for him again to accuse me of being on drugs and a cheat! I know I shouldn't but in a drunk rage I flew of the handle and everything over the past 3 years we've been through and all the times I've not been able to talk to him about certain things came up. To me it felt like a huge relief to finally say what I needed to say and actually give him a piece of his own medicine.but I know it's hurt him and I feel extremely guilty and I'm not sure how to apologise or make it right or what to do! I know he loves me and I do him but years of him turning nasty when confronted about relationship problems has tipped me over and now I hate myself. He childhood was also rough for him. His dad wasn't around and his mother an addict and was abused as a child so it's very understandable to have what he has. I've tried my best over the years to be supportive and patient but whenever I try ask him to do anything it's simply im not in mood. He has his days when real him is back but that's seems less and less often recently.