<human>: Context: We've been together 4 years, she has very few friends she can talk to, and has anger problems and other similar issues via abusive relationship with parents (no longer in her life) that have worsened over the course of our relationship. She insists I'm the only person she's ever loved and would otherwise live comfortably as a loner the rest of her life (even considered being a nun once), that said I am still her world. 

My problem is very basic and silly. I don't want a relationship anymore, but I am struggling to get out as I don't want to break her heart considering all the good she's done for me and how much I mean to her. 

I'm tired of her random tirades, explosions of bitchiness, talking at me for hours at a time, and interrupting me in conversations or not giving me room to say anything. I just want to be alone. Also, our sex has also been mediocre since the first year (She is what this sub would call "pro-sex asexual"), I've lost attraction to her, and I'm overall extremely depressed how much she has changed from the young woman I fell in love with.

On the other hand, I still do care about her, want to make her happy, and when she isn't behaving like a child, is a complete sweetheart. Ugh.
  
To make matters more interesting, we still have another year on our lease, and since she has no parents or friends to move in with and can't afford the rent on her own, I have to live with her for the whole time.

I've seen this said several times in breakup discussions: she IS NOT eager to find love again, so please save the "Stop wasting her and your time and break up so she can find someone else" comments. :/

Can you condense the text into three sentences or less?
<bot>: I want out, but breaking up would be one of the worst things to happen in her life and I still care very much about her, how do I go about it?