I used my best friend to set up my Fiancee … What should I do?

Dear Admin
My name is RoseMary, I used my best friend to set up my Fiancee in order to see if he will cheat on me. Men are so heartless, they change like weather. Now, My Best friend betrayed me and is now set to marry my fiancee, they have even sent me their wedding invitation.

I’m so devastated now…what should I do??
(Crying)