I rarely post here, just generally lurk, but I feel I have to say something here.
I was you, pretty much. I do understand. I know it feels impossible to leave, I know the feeling of turning into someone you don't recognise. I know you've made yourself smaller and less than you were and that all your valid feelings of resentment and hurt have been turned back on you until you feel like the villain.
I get why you will have posted thread after thread. I suspect you are a person who doesn't want to give up on things, wants to fix them, wants to make it better. And it takes time, not MN thread update times to make a different choice. It's hard, doing something different feels like a decision and then you have to take the consequences of that decision and own them, but actually, you are making a decision every day that you choose to stay. That's still a choice, and it has its own consequences, which IME are far worse than the consequences of leaving. I really recommend thinking about that, that every day you are making a choice to stay.
I left a relationship that sounds so similar to yours (alcohol, laziness, lack of care, gout, emotional abuse etc etc) when I was 34. I'm 43 now and so much happier. I was on my own for a while with my child and that was wonderful, and now I'm with someone who lifts me up, makes me better, supports me and (even when I am rubbish at it, because I don't know how to partner very well) builds a life with me. However, even if I hadn't met him, my life was already wonderful without the constant feeling of being dragged down and damaged by the person who was supposed to be on my side.
My ex never changed. He kept drinking, he kept ignoring his health issues, he kept alienating everyone who got close to him. He died of liver failure earlier this year, relatively young, because nothing could ever be more important to him than alcohol. I'm sad for my child and his other children, and sad that he never managed to recover to have any kind of life that meant something, but I am relieved that I made the choice I did, because nothing was going to change for me by staying.
It's also a shitty way for a child to live. I don't mean to burden you with that, it's hard to be told you aren't doing the right thing for your child, but with all my heart I know that my child is better for having not lived too long in that situation. No life is perfect, but neither of you should have to live in a home that feels less than safe or comforting.
Don't waste more of your life. As I get older I see how much of my good years I gave something that didn't deserve them and though I try hard not to be, I can, on bad days, feel very bitter about that. I try and remember the good things I got out of it, but it was a lot of time, and you don't get that back.