I want my soon to be ex fiancee to accept that it's over and be ok.?

I wasn't happy with the relationship so I tried to break it off. She said "she'd die" if I broke it off. I don't want her to be melodramatic or use emotional blackmail on me. I told her to be an adult about this but i'm not sure if she accepts that the relationships over. do I just wait for her to come to terms with it and not call her? or do i just simply change my facebook status from engaged to single in 48 hours?