Oh God, it sounds so familiar! We assume that when an alcoholic stops drinking that everything will be fine. Alcoholism is categorized as a mental illness. When you put down the drink/drug you're still sick. But in recovery an alcoholic can change if they have a program like AA and/or cognitive therapy. It takes a lot of hard work and years, but change is possible.
Your situation sounds dreadful. My answer to -- "never going to end" -- is that it's ONLY going to end when you decide to end it.