Espoir, welcome to PsychCentral (PC). There are a lot of great people here who might have some ideas for you and/or have lived through something similar.

Sounds like you have a three-way problem going. Don't know if you can solve what your boyfriend does with his ex-girlfriend or not, he has to want to stop her manipulation (yes it is) and break off with her if he wants. But unless he decides to do that or get help with his own feelings in order to do that I'm not sure what you can do with the situation since it isn't yours.

I would maybe research local help for her and give it to your boyfriend and tell your boyfriend you'd like him to point out where she can get help for her problems and that you'd like him to break it off with her. You would have to back that with an "or else" of your own that you are willing to back up. It is sad that your boyfriend is caught "in the middle" between the two of you but he has to decide what he wants for his own life and if you don't like his indecision, you have to state that and back it with "I do not want to live with this situation anymore. Do whatever you have to do to break it off with her completely or I'm going to have to leave you" and then do that. I think otherwise he will just keep her stringing along. It is not her fault that he allows her into his life. She has problems and needs professional help, his stringing her along is not going to help her, I don't know that he can help her at all. I would give her resources and offer to take her the first time somewhere but then I'd tell her not to call anymore because I want to move on with my own life and I'd change my phone numbers.

I had a boss who broke up with a woman who had been living with him for several years and she would not quit calling him so he had to get a legal injunction against her doing so and take legal action against her, etc. to get her to stop. It sounds cruel or heartless but sometimes the other person will not stop and manipulates anyway they can like your boyfriend's ex- so it becomes necessary to harden one's heart against them.