Please know this, one of the hardest parts to get over is the feeling that you can never trust yourself again. You were with this person and the expectation is that he will have your back, that he will never lie or cheat or whatever. That is normal, that is the way it is supposed to be. Because that is the way it is supposed to be you are left wondering what you did wrong not what they did wrong. I think we are raised like that. I too was a pollyanna. I tried everything thinking I could make it better, I had to because after a time I realized it was up to me because he was not going to do it. See how we do that?
Then you just give up, medicate yourself and feel like crap until you finally figure out what is going on....and then it gets worse. <-----this is where you are now.
It does get better but it takes a while to really begin to heal. I don't think I ever will heal completely but I am OK with that. We were never promised an easy time of it and now that I know how I got into the situation and understand why I let it go on so long I am OK with it. It is not your fault that you expected better, it is not your fault you tried to fix it all even at your own expense.
Do not ever expect him to understand. Some do, mine did and ended up in worse shape than I was and still is. Most do not. Deep breaths, cleansing thoughts when you start to panic. Pet your cat. Get some help if you can. PTSD is a difficult thing to deal with and it does not get better easily. Try to find someone who will help you and run out of the office if they ever blame it on you. You survived and tried to make it better, he did not.
EDIT because I forgot the