>>40576814 (OP)My ex told me about an ex she had who she couldn't break up with because she was afraid he'd hurt himself, so I just brought up that example when I broke up with her. She understood, and I think it made her take better care of herself after the breakup.
Maybe I had an easy button, do you have anything like that in her history you can relate it to so she understands your concern about her hurting herself? There's a line to walk here between motivating her "If I hurt myself it'll be getting back at him!" and connecting with her "I shouldn't hurt myself, I don't want to hurt him too"