In my experience, yep they do push us away, even if we are healthy and supportive. It sucks I know. I also think they are often confused and what they want changes from day to day.
You seem like a loving and caring person, he knows that so he isn't pushing you away out of spite or anger or anything YOU have done. You are internalizing things because as you say, you struggle with self worth issues.
I do too and those issues have nothing to do with the other person. They are all about your internal voice telling you 'I am flawed' or 'this is my fault'. The deeper question to ask is why you go to that negative place in yourself?
He said you DESERVE something better. That he knows you are worth more (and you are). That means he thinks highly of you. I am working on these issues myself but it is the stories that I make up in my head that are causing me the pain, not anything he feels or has done.
He did something out of love for you. In my opinion he most likely will change his mind. Either way he needs his space to deal with his struggles. He doesn't want to tangle you up in his mess and honestly, do you want to be?
And you can't help him get sober or recover from his disease. It doesn't work that way. He has to do that on his own for it and for himself. Use this time to gather your thoughts and feelings. You will be at a better place of understanding soon.. trust me
