Divorced moms: how did you do this without breaking?

After 10 years together, almost 7 married and a 3 year old son, I feel like I’m at the end of my rope. I’m not perfect, but years of his alcohol abuse combined with the resulting arguments and problems is forcing me to realize that this just might be irreparable. He has now admitted he needs to stop drinking and wants to stop for himself, but it’s almost too little too late. It’s hard to wrap my mind around it all, but looking back on my years of journaling my sadness and mental anguish and seeing the pattern that I am so afraid is going to continue even without the booze. I’m breaking my own heart, bc even with all this I still love him and the person he is and the life we had and hoped maybe could have again. The life we have that is good between the bad times. I had such a lonely and hard upbringing, and after finding him and being my person, I was so happy and relieved that now I had my family and I would have a life of happiness and holidays filled with joy and love that I always wanted and felt I deserved after what I went through. My brain is telling me the logic and reality of my situation and that if I stay I’m just signing up for more of the same, but my heart is still somehow hoping based on nothing. I am also just imagining my future of 50/50 custody of my beautiful son and missing the times with him that I deserve to have and expected to have, and the future full of happy memories we’d make as a family and as a part of his big beautiful family that I love, of nights where I’m crying into the echos of my empty house with no one to comfort me, to days where I turn to share a funny story or how my day was and no one to be there to share it with. Or my anger and resentment that this would be my life and it’s not what I want at all. This anticipatory grief of this future that seems inevitable is breaking me, and I don’t know if I can handle this without just crying until I am the empty husk of a person that I will now be. Bc let’s be real, it’s pretty clear that my future as a 40yo single mom isn’t going to make for a lot of potential future partners who’d want to take that on in a serious relationship, so going this path will most likely mean I will be alone for a long time if not forever. For those who went through this, how did you do it without just totally breaking?