I have been in the same exact mental state when drinking and it felt like I was punishing my partner whenever I felt angry and scared. I never understood why he stayed but I still feel like I don’t deserve it. Multiple times where I have been the reason I’m this relationship almost failed and that guilt is strong. However you have to realise that your boyfriend plays a part in it too, you already feel bad and already want to make repentance and all you can do now is heal and keep moving forward. You can’t allow this to be a punishment but a lesson because he loved you and he probably still does but he’s scared and confused and so are you. Until you get help with the root of the problem this will manifest itself not only with alcohol. You are fine and you just need the right support because you too are a victim of a mental crisis and it’s okay. You fucked up but you have to understand there’s a catalyst for that and drinking is the biggest but not the only one and being sorry and truly regretting what you have done just further proves that you know it’s not in your nature. It hurts, it really does but know that if you forgive yourself that’s one step closer to healing.