I think what Dee said is so simple, and really is where I was when I quit. "Drinking isn't working for me."
You said the ex is toxic. He has no say in your drinking or how to do it. He also drinks a bottle of wine a day? He has his own problem then.
Just don't drink today and go to bed sober. That was the only thing on my To Do list in the first couple months. I don't drink, never will again.