Dear Iworry4him,
I've just come out of a 3 year relationship with a sufferer. Although he really loves me and wanted me in his life forever, he just couldn't include me. He wanted a totally different kind of relationship than what the average person finds normal. I felt alone, excluded, isolated, shelved. He often told me he loves me but he just is commitment phobic.
What I want to tell you is this: Just as supporters, sufferers also come in different characters. Some find comfort in relationships, others find it hard to open up and fully commit. This has to do with the ptsd to the extend of their own personality. I've seen many sufferers on here feel better in the comfort of a r-ship and others run away from it because of stress, commitment or other things.
Like BloomInWinter said, and many other posters gave me for advice: Think about what you want in life, and what you want in a relationship. If you hold on, you might become co-dependent.