how do i break up with a psycho g/f????

exactly. let me put this into perspective. her mom is a single bi-polar alcholic, who continues to date on and off a guy that has beaten her before, and she even has a standing restraining order against. her father and mother we not married when she was born, and he used to beat them both, she no longer acknowledges his existance. her grandfater who basically is her father due to above said situation, has had three open heart serguries again, and hes looking like he needs a pacemaker now. her grandmother is getting MADD alzheimers, and the rest of them are alchies. she hates them all. i am seriously the only thing she looks forward to. i hate it, because thats a huge load on my shoulders, and im sick of being her crutch. all she ever does is dump all her problems on me about how sad she is about someone sick or someone being dumb in her family, or how her and her mother fight on a daily basis and just keep telling each other how much they hate one another and hope the other would just die already. this is seriously some fucked up shit and i have to get out, cause its bringing down my morale