While I can in a way sympathize with what he's going through, I do believe that he is going about this in...not the right way. If he needed time away, to be alone...he should have been the one to leave. Making you leave and stay with his parents, totally up-heaving your life like that truly is not fair at all.
I hope that he will warm up to counseling...because outside help definitely looks like the way to go here.
Something that stands out to me though, and I hope that I don't get flack for this, because well, I guess I'm coming from a place where the things you've said about him, that he has told you, I feel quite a bit of myself (but it doesn't affect anyone deeply because I don't have marital responsibilities) is when you said all hes doing is care about himself. But also recognize, that you care about yourself too, and in a way, a lot of what I'm reading is how he needs to change to alleviate the anxiety and problems you are having so that you can cope.
Not saying right or wrong situation mind you, just pointing out that both of you seem to be in a mode of wanting the other to do what would make your personal selves feel better. And likely, due to his PTSD, and what you described and recognize, that he's feeling hopeless, that you would be better off without him, questioning his worth...it really doesn't seem that he is thinking all about him, but more that he's in a pit and actually does mean what he's saying, that he genuine feels that he's doing you a favor because he feels so low about himself right now. Add to it that you have your own issues as well, he's in a position where he's not only responsible for himself which he cannot fully handle, but also responsible for you and your happiness as well...which can be overwhelming when you don't feel worth it..the higher the pedestal, the harder the fall, you know?
Anyway, just stuff that came to mind as I read through all this. I do think that you should be the one to stay at your home...he's the one who wants to be left alone, so he's the one who should have left, not you. But I also think that it sounds like you need to focus on yourself, to do what you can for the issues you are facing because relying on him to help you through that doesn't seem like the best game plan at the moment. He's in a hole and will drag you down into it..well, he already has actually.
I totally believe that in time, he will have that moment of clarity and turn around, I mean, this whole thing does come with its ups and down. Just that I couldnt say wither putting a time limit on when he should be okay..be it 3 weeks or a couple months or what have you is ideal, or just giving him more pressure to "get over it" in a way? It sucks to wait around...and I personally dont think you should. NOT saying to give up on him, just saying, if he's in a really dark place right now, just waiting day in and day out for when that darkness breaks will tear you up.
Id focus on getting back in the house where you feel safe and have the comforts of being at home to feel centered, and do your best to work on your issues. Also work on being less dependent on him emotionally, work on getting a job so that you have your own stablility / routine instead of having only him to focus on all the time. In other words, you deserve to think about you, and what will help you feel better to get through this too.
