Whilst you say that "he is not like that" and you are basing that off his past, let me assure you now, all that is out the window and you're going to need to differentiate between past and present, because the two are no longer interconnected if he truly does have PTSD. He doesn't care any longer what he used to do, or used to act like, etc. What he will do now will not be rational, he will not be able to understand why he is doing certain things, he will no longer do or act like you knew him too do.

Yes, if you cut communication with him he would take hold of the "I don't want you, though I don't want anyone else to have you either" routine, however; he will not love you in the same way and he will cheat, he will be out, he will be violent and/or emotionally abusive to you. Sorry, but if he has PTSD he is now in a completely different world, all of which has developed within him over a period of years through deployments.

You can no longer apply the past to the present with him, as they will not coincide any longer as you once knew. Sorry, but these are the facts of what your about to experience. He must find himself in order to work out whether he wants to have you as part of his life once again, without abuse and so forth. He will abuse you otherwise, he will mistreat you, he will do all this and more without knowing why. He must go and learn why in order to understand how to fix himself.