Okay Glara, I know it's hard but take a breath. Stand still and try to relax, even just for a second. If you feel awful for not texting him, text him once and just tell him you're here to talk and you're here for him. You've just found out about his PTSD, maybe you should look around and post more on this website - it might help you understand what he's going through and such. You could, possibly, text him and say "Are you okay to talk? I'm not feeling very good." or something along those lines, hopefully he'll realise you're unhappy right now with your daughter moving out and maybe he might be the type to feel better when helping other people (like my boyfriend, it helps him to help me and I'm the same).
So you can either go to a friend or talk more about it on this website and wait for your partner to be back to talking again before talking to him about it, or you can text him and explain you're not feeling good and would like to talk to him. If you chose the latter, don't blurt out all your problems before checking you're okay to do so, with him.
Like what
@Solara said, it wont hurt to text him. If he isn't up for talking he'll either reply saying so or not reply, which isn't the end of the world I guess. You can then assess how you feel about that and such and if you need to, seek out the help of a friend or even a therapist if you need help dealing with his PTSD symptoms as well as your own.
My boyfriend described it to me as he's now not only dealing with his own stresses, but also mine, which is tough apparently. For me, my boyfriend supports me by helping me deal with my own stresses. So he has half of my stress, plus all of his, whilst I only have half stress.. that's weird to explain but yeah. So, don't be afraid to seek therapy, it's not just for officially diagnosed people, it is also for people who need someone to unload on and seek advice from about emotional and even relationship difficulties. And like I said, you're welcome here, to post and rant and unload on us. We're happy to listen and help.