Not once has anyone said that folks with PTSD are not worthy of love. They aren't aliens, they have PTSD, and are as worthy of love as anyone else. However,as Nicolette said, it's the undying love for someone who has basically kicked the supporter to the curb in more ways than one, and when you point that out, you are unsupportive, that gets me. I think a lot can be attributed to age, or rather, lack of it, of the new supporters and probably their sufferers. Neither has the experience to go about long term relationships properly in the first place, and I think we have all been there at some point in our lives. But you have to stop beating a dead horse, when he/she disappears.
"It's not you, it's me," is one of the oldest dumping lines in the book. Along with "I'm not good enough." Lets you down easy. How about "I'm just not that into you?" Now there is an honest line. I get that sufferers do truly think badly of themselves, but if you take those lines along with the bad behaviours, then you have someone who has already moved on. Don't blame yourself, or PTSD. It isn't Kharma, it isn't fate. It's not a momentary lapse in the judgement of the sufferer. It is just the way it is, and your relationship is circling the drain.