Girl from my past is trying to sabotage my engagement?

My EX girlfriend Chelsea called me yesterday asking me if was true i was engaged. I told her it was.true and i can't wait. She told me I'm making a mistake and i should marry her. I told her it's over between us and i don't love here anymore. She said i was lying and my sister told her i had be asking if i would be interested in hooking up some time since she gave me the best i ever had. I told her that was a lie and that i love my fiance and i moved on from her a long time i ago i suggested she do the same. She send me some pics and asked me to change my mind i declined. I dated her during high school and lost my virginity to her. I loved her and did get her a promise ring but she started acting like a slut and i couldn't handle it despite her being great in bed. The bad outweighed the good. My fiancee Kayley is kind and gorgeous. The only problem is she isn't crazy about . She likes it but will only do it when she wants it and never when i want to. Chelsea was always willing to sleep with me and has a very high drive. She told me she will make sure she ruins my wedding because i belong to her. What should i do?