I have been friends with one girl since secondary school. However, she hasn't been a great friend. When I did better than her at Uni, made more friends etc she would always be very negative and put me down in front of people. This eventually came to a head and I have decided to cut her out of my life. I was very open as to why I was doing this and said so to her face. However, she has spent a lot of time slagging me off to joint friends behind my back and pressurising them to stop talking to me / not invite me to events. I have not said one bad word about her to our joint friends. Understandable I am very upset and angry. I know a lot about her past that our other friends don't know. Including lies she has told, engaged men she has slept with and trouble she has started within the group. Do I spill the beans in an ultimate act of revenge?