<human>: Give me a shortened version of the text

Errrr. Well, I didn't really say "errr" but I definitely felt it.

There's a guy that I have had a very off and on again relationship with for the last - let's say... five years. A week ago, he told me that he loves me and asked me to be his girlfriend. I told him that while I do love him, I need to think about getting into a relationship with him simply because we haven't worked in the past - he has a history of shutting down and becoming this thick wall for no reason (at least, he never explains the reason) and I also want to give him room so that he can find someone who may be better. We would be in a long distance relationship and it makes me a little insecure.

While he still tells me that he loves me, he's now starting to ignore me and is shutting me out, which is majorly confusing. I love having him as my friend, but my gut tells me he's losing interest. Should I end the friendship? His cold behavior just make me feel like there's something wrong with me. 

There's also this: He is an Iraq war veteran. He has told me about his PTSD in detail - about his nightmares, his painful flashbacks and guilt... among other things. I know that PTSD isolates its sufferers... but he won't communicate with me, and I'm unsure if he just wants to move on or if I should stick by him and be there while he tries to resolve his problems. 

If anyone has any good resources on PTSD and how loved ones can come to understand and communicate with their partners - I would greatly appreciate that. 

* I first posted this in dating advice, but deleted it since this forum seems more appropriate. Thank you all for your insight!
<bot>: Old friend/lover wants to try again, I want to take it slow, he's shutting down. I also feel lost, helpless, scared in his PTSD.