I have been searching for answers, and feel like this forum may have a lot for me. I am in love with someone with PTSS or PTSD,I'm not sure which, but I think it would be the latter from what I have read and experienced. The feelings you have are very similar to how I felt when we were first together.
We have an intuitive connection and fell in love quite quickly. But it did all fall apart very quickly, I'd advise to remove any drugs or alcohol from the equation for a clearer picture.
We're getting back together two years later. I still love him and the feelings have not gone, only stronger. But he has not gotten therapy yet and won't be able to do so for practical and financial reasons.
If you are feeling emotionally strong, you will have a lot to give. CBTherapy always has to get worse to get better. Our mind is a series of drawers, and it is very strong/clever, and sometimes, it hides the keys to a lot of pain.

It's very frustrating to not be able to know what to say or do when things are bad. It's like trust is such a major thing for him, and I want to show I care, but I feel like I ned to leave him alone to fight his demons, yet I don't want to. I know that's confusing. I'm glad to find others similar to me here.