She had a lot of severe MH issues. We'd been best friends for 15+ years and I supported her through EVERY in-patient stay and 4am suicide-threatening phone call.
But in the end nothing I ever did was good enough for her. I wasn't supportive enough, I was selfish and apparently I had no idea how much she did for me (spoiler alert: looking back I can't think of one thing she's ever done for me).
Her constant accusations and lack of empathy were having a massive impact on my own MH when I was going through a tough time and she was totally uncaring about it when I tried to confide in her. She twisted my issues to be about her and I didn't have the energy to take on her burdens as well as my own anymore.
So I ghosted her. I felt so guilty for months and months. But it was impossible to talk to her and she would have twisted it to make it all about her. But it wasn't. For one fucking time it was about me and I needed to put myself first.
It's been a couple of years now and I don't regret it. I also dropped a couple of 'friends' who massively enabled her and tried to guilt-trip me into going back. Predominately because they didn't want to deal with her attention-seeking and general woe-is-me attitude.
I later found out that she had told a man that I was dating at the time to ghost me (a few months before I ghosted her) because I had too much on my plate to deal with and I wasn't in the right headspace for a relationship. Actually it was because he was "her" friend and she didn't appreciate him and I doing things without her. I also apparently committed the cardinal sin of not asking her permission to date him (WTF we were all in our late 20s and I'd been friends with him for 10+ years). I also found out that she'd spread some pretty horrific lies about me over the years, for no reason.
I am sad about it sometimes. But then I realised that she isn't the same person that I was friends with anymore and I've changed a lot too. I've had to accept that the person that I was friends with doesn't exist anymore and I don't think she'll come back. I still keep track of her, because I do care. But I have to put myself first.
All in all, I'M VERY WELL RID OF HER. I'M HAPPY. (Gosh, that was very cathartic to write out.)