It is amazing how many similarities there are between our stories. Ironic that he was originally a psychology major. What kind of law are you going into? I am an engineer and my H didn't finish college. It never bothered me because like you that didn't matter to me...but I think it did to him. He joined the Air Force and now is faced with major career decisions as he will be getting out in December.
That is good that they have ordered an evaluation. If he is hurting himself then it doesn't matter if he is mad about it...he will get over it when he gets better. When you get mad at him for all of this just try to remember that he has seen and been through things that you and I can not even comprehend. Is he on antidepressants? Sounds like he should be and they will probably figure that out when they evaluate him. It is good that there is a lot of distance between him and OW. Long distance relationships are hard under the best of circumstances.
So many times I have thought to myself that I should have been worried about H instead of mad at him. Try to remember that. I think he definitely has PTSD. Just try to give him space and don't pressure him. You sound like you are doing very good.