I could comment on the notion that one owns one's girlfriend but regardless, you should definitely self host if you're sharing deeply personal information with a program
I'm thinking through it and I don't think you should run a therapist off your phone either. Not even for privacy reasons, that just seems like a recipe for disaster.
EDIT: It seems the app sherpa has what you need. Just use one of the models found here, preferably 7b-chat Q4_K_S
Some people are energised by that kind of thing. However if you don't want to reveal things to humans, you can use (if you are more technical) llama.cpp