Thanks for your post. It resonates with me. I know for a fact when (I'm not there yet) we split he will get a new girlfriend quickly. He practically told me so. That will hurt because my husband really can be fun to be with - or, now that I think of it, he was fun to be with.
I can't stand to be around him with a drink in his hand, much less after a night (or day) full of drinking. That's the reality. That's the guy I don't like and don't want to be with and the time with him drinking is becoming way more often than the time of him not drinking.
I guess what I'm trying to say is that I can share your feelings because as I play the movie to the end in my mind - I see him with a gf and feel just horrible. Then I realize he's not for me.
At some point, I will need to let him go. And you will too. I'm certain the on the other side of hurt and pain is feeling of freedom, peace (!) and happiness. I'm certain of it. It's okay for him to be happy. It's okay for you to be happy too. I think that's actual win-win. But it's hard to see that now.
I will be very, very sad when to know my a is with someone else. I hope I will be able to get to the other side quickly.