Setting boundaries with others who blame (or refuse to take responsibility) is tough to stick with: it's ok to shut off the phone, to not answer the phone nor the messages and to not go out with someone you don't consider fun!

But it sounds like you want to be able to do stuff with her. Make sure it's her problem and not yours (which you are probably doing through therapy.)

Can you choose something NOT at your home but meet her somewhere else to do something? That way you will be able to leave and get back to "safety" of home. Give her a time limit... ok but I have an appointment so I can't stay long... (an appointment with sanity at home???) just thinking aloud.