I'm so sorry that happened to you, Sadeered. It sounds like you worked really hard to try to make a go of it. If it's any consolation, it sounds like he does need to work hard in therapy, perhaps get some adjustments in his meds, etc. Evidently he just can't deal with a relationship very well with his current circumstances.
It could even be that he has an additional mental disorder that's causing some of his problems, and he would need to get help for it, too.
I hope you can feel good that you tried to stay with him--through lots of thick and thin. Just trust that he knows what he needs to deal with. I only hear one side of the story, but it certainly could be that whatever mental issues he is dealing with caused him to say what he did.
If you do find that you just can't let this situation go, then you might consider talking to a therapist about it. Okay? I think many of us have had relationships end without knowing all the answers. You only knew him for a relatively sort period of time, so there were probably some things he hadn't told you. Just a guess, anyway.