Losing a great relationship do to my mother

I have a wonderful girlfriend who is on the last string of hope. We on a break now do to my mother. Reason is that she has anxiety and panic attacks to where I can't leave to have a actual relationship. For the past six years of my relationship, she has been mostly coming over her and of course only so much a person can handle. My mother promised things would get better. actually it was "give me two more months". Those two months turned into 6 years and it already cost me one relationship where I really liked this girl but she quickly left after realizing I couldn't leave which made me develop depression and mentally damaged me. Now current it's happening again and I don't want to lose this perfect great person who has been completely amazing to me. I'm just stuck because my depression and anxiety gets worse when I try to talk to my mother about because all she does is get verbally aggressive and defensive when I try to tell her how I feel. Everytime I try it ends up in me snapping and walking away. It hurts because all these years of her trying she rarely tries. All she does is watch TV day in day out and not even caring how I feel and importantly what makes me happy. I'm just stuck because I don't want to feel like a piece of shit son but also I don't want lose the true love of my life because of my mom. I'm just stuck😥