Most of drink excessively because we're in pain to begin with. We stuff our feelings, don't talk to our partners, sometimes we've put up with abuse, and bad relationships, etc. But you gotta start somewhere, and that's with the booze.
Quit the booze and you can start to sort out the other stuff. Plus, it shows you've acknowledged that there's a problem, and you're willing to work on it. Who knows what will happen with your relationship? Whatever you do, don't stay in it just out of guilt - I've made that mistake.