Poppet....one basic principle about relationships, that I especially remember, as written about in "Co-dependent No More"....is this.....
Whenever a rescuer enables a person that they shouldn't---eventually, it gets turned around, so that, the enabler become the victim and the one that was enabled becomes the perpetrator....
I think that I see that at play in your relationship---you have become the victim, and she is the perpetrator.....as Airesagain said...she is a bully and you are feeding it....bigtime.....