I understand why you didn’t want to tell the “big issue” and I honestly had no idea it was anything like this and I am not going to focus on it because you are right… it is a part of things but not the end all. That can be worked out and dealt with.

What I am not understanding is this:

You say over and over (and that shows me how importance this is) that it would be just wrong for you two to part ways because you both want to be together.
Yet he is taking things out on you and now he feels he cannot continue the relationship if I am hearing you correctly.
If he is spiraling downward into a a bad place then he may be feeling like he cannot hold on to you in the way he knows he should.
Maybe he doesn’t want to hurt you.
I believe in prayer and in situations like this one, it is the only way to peace.

I hope you two can stay together. It sounds like you have a lot of good as well as bad.