Hello and welcome to the carers.
I don't have much experience in what you are going through.. but having read lots on this board it makes me think that maybe your husband won't admit to himself he is sick? That he maybe hasn't looked into what PTSD is.. thinking the things he is feeling and going through are in his head or its "just him". Also with military I have heard many times its almost implanted into there head sort of that they CAN"T get sick.. especially mentally. Its a weakness that should be denied sort of. It is true he must do the work himself to get better.. and it is VERY hard work. But as a first step you might tell him you have been researching PTSD and if he is responsive maybe print out some info for him.. or even try and get him to check out this site himself. There are lots of military people on here that he could connect with and it might open his eyes that there is help for him and he could get better.
anyways.. hope things get better for you and feel free to ask any questions here in the carers section and also in the other sections for some info from the sufferers point of view too.