Grinding isn’t great but wow is it really as unforgivable of an offense as everyone is saying?? You’re clearly extremely remorseful and we’re being quite honest with him. If I had to guess, it’s probably a bit of resentment for him not being able to be there with you seeping out. I’m in a mid distance relationship also and know how hard it can be. Even harder than long distance in some ways. Those little cancelations when you were excited to see the person. Missing physical contact because you’re somewhat used to their presence. It sucks.

Now I’m not excusing your behavior but neither are you. Being drunk IS valid especially if you’re drinking to the point of not remembering. I think the best thing to do would be to drastically cut your drinking or stop altogether if it’s really bothering you that much. You crossed boundaries and for that you should be sorry and respect that the ball is in his court. But a lot can be solved with communication and honest conversation. I think it’s silly to pretend like there was no reason for your actions rather than critically thinking about why it happened and confronting the issue head on.