Vent away, like someone else said, you are here, in a safe place!!
I remember when my X went to rehab. I expected so much. He stayed sober for a year. He was the same a$$ sober as he was drunk.
I stayed with him for years after that. I divorced last year. I was feeling just as you are. Anxiety. Despair. We tried marriage counseling. It was not productive.
There comes a time where you have to just realize that staying together is not always the right thing to do.
Hugs. We support you no matter what!