My mom f50 got into a relationship with my now stepfather M50 3 years ago. For some context, before this it was just my mom and I(f19) for years. We had our troubles especially after my dad left but we went through a lot of therapy and got very close because of it. Now, I am back home from college for the summer and I feel like I'm going to go crazy. I never really liked my Step Father but we have gotten along because of how happy he makes my mom (he also has his own struggles from a troubled background and BP).
Recently he's expressed that he doesn't want to push me away but that he's going to start telling me what pisses him off abt me and what I do. (Pisses is his word not mine) Which I feel like would be fair if he had built a fatherly relationship but he hasn't. He would be a complete stranger to me after 3 years if my mom didn't keep me updated and in the loop. He makes me so angry and I feel like l'm starting to build resentment against my mom for her bringing him into our lives. My mom is putting a lot of working into helping him improve himself and it’s slowly working, and in great news they have a significantly happier and more functional relationship when I am not in the house. That being said, he not only makes me feel like I have to walk on eggshells in the house (note house not home) but he puts immense financial and mental strain on my mom. That is what hurts the most to see.
I know my mom will never leave him and after this summer I won't be moving back home again. I'm riding the storm until school starts again but l'm conflicted about what to do after that. My heart wants me to tell my stepfather I don't want a relationship (which could also be a trauma response because I had to do the same with my bio father for a few yrs) but if I do that I risk losing my mom as well. Should I just keep pretending we're a happy family? Any advice would be greatly appreciated. Above all I just want my mom to be happy and I will sacrifice anything including our relationship for that.
TLDR: Stepfathers Strained Relationship with Stepdaughter makes her question leaving her close family as a whole for the greater good of her mother