I'm sorry you are going through this, but you're in a great place to get support in helping you make the decision that is best for you. Being stuck in the hurt and indecision that comes with doing what your head is telling you is the right thing to do, but your heart - for some reason - is still willing to put up with, is not a pleasant place to be. It is an unrelenting war within.
We all have different reasons for staying, but a common reason for leaving - when we finally decided "enough is enough". But only you can decide when you have had enough.
Why did I stay? Because sober, he was an amazing person. A caring, thoughtful, genuine, funny, educated, hard-working, financially stable, respectful, and generous man. Everything I had been looking for in a partner.
Why didn't I leave? Well, you might think it was for the same reasons I stayed. Aren't they the same? Nope. I learned the reason I didn't leave just the other night when I found the courage to attend my first recovery group meeting at church. What I had intended to share was so very different than what I actually shared. In my head, it was all about him. But in my heart, it was all about me. I found myself sharing that I struggle with fear of abandonment and low self-worth. I'm never "good enough". And when a relationship begins to fall apart, whether through time or circumstance, I hold on for dear life - in a futile attempt to prove that I'm "good enough", and to avoid being abandoned. I don't let go, even when I *know* it's in my best interest to do so. I hang on until the other person finally says "enough is enough" and lets go... and I'm left dealing with the damage my inability to let go has caused me, which only serves to further reinforce my feelings of abandonment and that I wasn't "good enough". In my relationship, I thought if only I was "good enough", he'd choose me over the drink.
Your reasons for not leaving may be very different from mine. But if you give an honest look within, you might find - as I did - that they have everything to do with you, and very little (if anything) to do with him. Be gentle with yourself when you find those reasons. We are all a work in progress.