I try to think of it like an abusive relationship.
Sure, there was a time before the abuse started that you thought alcohol was the love of your life. Everything was great and you thought you'd get married and be happy ever after.
Then came the getting jealous over other things in your life. Demanding more and more of your time and attention. Hurting you, just a little at first, until you got used to it and them ramping up the pain.
Controlling you. Telling you what to do and when to do it... (You need a drink now. No, you can't go to the movies, there's no alcohol sold at the theater). Telling you who you could spend time with (Do you really want to hang out with ______ when they disapprove of you drinking?)
Destroying your health, your piece of mind, your finances, your relationships, your sense of self, your boundaries about what is and what is not ok in life.
And just when you get ready to leave, reminding you of the good times and promising to change. But then as soon as you agree to stick around, the abuse ramps up even more.
It is hard to leave. But the longer you're gone, your sanity starts to return and you'll start to wonder how you could have ever put up with the abuse for so long. Sure, there will be times when you miss that dream of living happily ever after together. But that dream was never going to be the reality. Sure, you'll miss the good times... but then those were fewer and further between until they became practically non-existent.
Mostly you'll be thankful to be free. To have your life and your sanity and your friends back and not worrying about when the next time alcohol is going to hurt you again.