Threatening or blackmaiing to marry

When I started working in a particular work place, i casually interacts with people. I had and have a caring nature too. Based on this, i found a colleague attracted towards me and she proposed me. First I denied and then i accepted her request, and our our relationships lasts an year and half long.But after acceptance only i came to know many things 1.Her previous marriage gets stopped over an year due to an issue that the bridegroom was already married and got divorced. As a result of that, the got 4 and half laks money from him as compensation in addition to jewels he gave. 2. She had one side love to some one 3. to get her her research work done, she flirt with people to get anythng done. Based on this, i got an evidence also a chat between her and a guy,, regarding he is calling her to a particular place and do intercourse to get the work done.she also visited him But when i cam to know this, I asked what has really happened there, she replied nothing happened. 4. a forgery in getting a caste certificate to get admission Even during my relationship, im very true..sacrificed many things. But later I came to also got used by her for her research work by editing and composing research papers, making ppts., etc.. But I had kissed her, roamed with her,touched her, but never had physical relationship. But one thing i did wrong is i assured her that i will marry.I came to know all above things after these only. So i started avoiding her.Shifted my work location. Even after that also.. its been two whole years.. She is still threatening or blackmailing me to get married as she got some pics with me.What should i do ?