Im so sorry to hear that your girlfriend is suffering the symptoms that PTSD does to a person. First of all I'd like to tell you I pray for PTSD sufferers and their families often, as I have been through it after my sibling committed suicide as well as my family, and was recently in a relationship with a Iraq war veteran who suffered with PTSD and TBI (traumatic brain injury-causes mood swings, difficulty remembering things, depression, headaches, dis-coordination, etc).
Yesterday we broke up. I didn't see it coming, in fact I saw us getting married in less then a year and having both of our's first child soon after that. The last few months got progressively worse in the area of being emotionally distant and more and more irritated with me for no reason. He wouldnt stay on the phone with me for more then a second let alone any reason that wasn't important. Wouldn't shoot me a text to tell me he's thinking of me/missing me/wondering what I am doing. So I started feeling more and more alone (without being alone), sad, forgotten, uncared about, and just plain old useless. He's refused medications and or therapy for the past year from the veterans hospital because he believes marijuana is the answer to all his problems. Although even with his marijuana (supposedly what works for him) he got progressively worse after the few first months of our relationship (together the past 8 months, known each other for 12 years, both us being 24 years of age today) wouldn't do anything he didn't want to do. Not even go for a walk. All he wants to do is be in his room at home, or at his aunt and uncles house where he could smoke his weed or go camping every 3 months or so where he could smoke his weed. sit around and watch tv at all these places.
I thought we'd get married and have kids together, I decided to call it quits yesterday because he is completely emotionally UNAVAILABLE. And I have BEEN trying to be supportive and understanding. I obviously wasn't helping him in any positive way whatsoever. So I told him how alone and hurt I've felt and he disregards it completely because he is too centered and focused on the things that hold him back. So... now that I shared my experience with you I'd like to also say (i believe someone else said this too) no one will know when it's time for you to throw in the towel, except you.... It's so hard to do, let alone tell someone else when they should say good bye. Best of luck to you and hang in there if you decide to and move on when you decide to move on. God Bless..