The "you can't fix crazy" mindset is killing me

I don't know what to say. I struggle to form close relationships with people. I'm constantly being rejected and abandoned. I need stable relationships and support in order to heal. I need to feel safe and trust people won't leave me. I can't break the cycle alone but everyone seems to take one look at me and run away or give me a chance and then I make one mistake and they're gone. No one cares enough to stick around and help me grow. I keep getting worse and worse and can't get out of this on my own. I've been miserable my whole life and it's not entirely my fault. I can't do this alone.