Familial and domestic emotional abuse

My mother tries to control every bit of my life, and when I don't acquiesce, she contacts my SO and blames him for taking me away from her and ruining our family. My SO says he's tired of my mother meddling with our lives, and he thinks it's going to be like this forever if we continue with our relationship. I say that it will not be the case, and the reason as to why my mother still feels like she has some kind of say in my life is because she still supports me financial in college (and happened to raise me.) My SO says the entire thing stresses him out, and he doesn't deserve to have to deal with that when he's a grown man and trying to focus on starting a life. Both are trying to pull me one way or the other, and I just wish they'd listen to what I have to say for once -- yes, I do have the ability to make choices for myself without my mother's input, and no, my relationship isn't always going to be influenced by my mother. No matter how much I try to rationalize and communicate this to them, I end up being the recipient of slurs about my being weak or spineless. Help? :(