I think first you have to be good to yourself, and change your expectations about what your partner should be doing. With my own PTSD I find I need reassurance from time to time, you know those little messages that you get that tell you "You're OK" or "You're loved" or "This too shall pass". And I simply can't get those from my BF. It's not that he doesn't want to say them, he's just so wrapped up in his own stuff that he simply doesn't think of it, or realize how much I need it. Talk about feeling lonely!
Fortunately, (yeah, not really, but I'm trying to make the best of it!) I grew up in a family where they didn't do that either. There were no tender words, or anything to bolster you if you had a bad day or were feeling down. If they said anything, it was along the lines of "Snap out of it!" or "Grow up!". :-( So I'm kind of used to not having those affirmations.
The people we love and who love us should be giving us those positive strokes, those "warm fuzzies" that we all crave. But with PTSD sometimes they just can't.
So we have to do it for ourselves, and find substitutes. This forum is great for getting a "Way to go!" or "Well done!" when you need it. There is so much love and support here. Funny that we can get it from people we don't even know, via an electronic medium, and can't get a physical hug or words of love from our own S.O. But whatever works!
For me, I decided to just not expect it from him. If he does say something wonderful, and occasionally that happens when he's feeling more like himself, that can fuel me for months!
Big hugs from me to you PTSDcotherapist. Think of it as a little warm flame from my candle to yours, to help get you through. You're in the right place, and we share your feelings of confusion and loneliness at times. We're all here to help each other.