I don't take the high road so much regarding revenge when it comes to principles, but I do when it comes to the practical. This bf of hers, do you think you might ever cross paths professionally? If yes, then it would be very wise to vacate that relationship ASAP.
People do so many mean things in this world. My guy finally let me see his texts with this socalled friend. Turns out she had used what he told her about me as reasons that he should stop dating me. And he wanted me to see her as "just a friend?"
These days I take a certain pleasure that my guy slowly unraveled his relationship with her. Couldn't make it to her b-day party (the invitation was sent the day of anyway) Stopped returning texts. Didn't wish her Happy B-day on her FB wall (which was 2 weeks later). Detagging photos on FB. "Defriending" her. I just couldn't be a gf to my guy with this "friend" lurking in the background.
So, OP, perhaps you can find a slow drip way to wreak revenge on this woman. One in which you are effectively excersing your rights as an individual, but at the same time, you also know it will annoy the hell out of her.