You sound like a wonderful mother, you remind me of my mother honestly. She always puts my needs before her own needs.
I want to share just one little thing from my relationship with her: I once came home from school to find her on her own in her bedroom crying her eyes out. She had never let me see that sort of strength of feeling from her before so it was clear to me this was really serious.
She explained to me then that she was really really unhappy in the relationship with my step-father and she had been for years, but she didn't want to disrupt my life and she didn't want to seperate me from him because I was so close with him.
She had basically prevented herself from being okay and happy because her highest priority was not disrupting my life, but really I couldn't have cared less about that dude, or the house I was in, or whether we moved away, I just wanted her to be happy, because I could tell she wasn't. She was sad and it was obvious that she was even though she was doing her best to hide it from me. Living with that sadness was worse than whatever disruption came after.
I wish I could have told her years before that I would support her and she didn't need to sacrifice her happiness for me, especially because she was assuming that leaving my stepdad would be really really disruptive for me, and it just wasnt.
Kids are really fucking resilient. I know that you will always put them first, but I hope you can get your oxygen mask on too if you get what I'm saying.