<human>: Can you summarize the given text in a few sentences?

Ok, let me start off by saying we were together for almost 2 years and we've had our share of bumps in the road. She started living with me about 5 months into our relationship, and I care for her dearly. She comes from an abusive background and has been diagnosed with Borderline Personality Disorder. For those who don't know much about BPD, she suffers from impulsivity, intense anger, and unstable self-esteem and emotions. The beginning of our relationship was great (I suppose we were in the honeymoon phase), but after a few months, our sex life came to a screeching halt. I tried talking to her about my issue with this and tried to be understanding as I know she's been abused in the past, but nothing ever changed. I went to my hometown and hung out with a friend of mine, which turned out to be a huge mistake. We ended up kissing. My then-gf found out about this through social media, and nothing was ever the same. I hurt her so much. Since then, we've had these intense emotional fights where she gets in my face and constantly brings up my infidelity. She's hit me out of anger a couple of times, not hard enough to hurt me, but still. When I say I don't want to talk anymore she accuses me of not caring or not having emotions and then locks herself in the bathroom and cuts herself. Recently I came to the realization that this relationship isn't healthy for either of us and I called it off, but the problem is, she's still living in my apartment, and it BITTER. For example, today I ordered a sandwich delivery, and she comes in with food in hand. When I told her I already ate, it escalated into her berating me for not giving a shit and bringing up every wrong thing I did during our relationship. I don't know what to do at this point. When I ask her to leave, she threatens to go back to her abusive ex. I know I made mistakes, but I can't help but feel manipulated and stuck.
<bot>: Ex-gf has borderline personality disorder, still living in my apartment, driving me crazy by starting fights with me.