I'm no Doctor so cant diagnose , she could have Bp or borderline (sure fits that mold) or both and more.

If she is willing to go into treatment and work like helll then its possible this relationship will work out.

Lots of people find a Therapist and try some meds and just blow it off as it takes enormous will power to follow through. Maybe she will be willing to do the work...

It would probably be very helpful for you to see a Therapist on your own to help decide if staying with her is going to be healthy for you

Welcome to PC