It's bad to cheat when you are engaged to someone.
Rosie is due to get married tomorrow, and she's starting to have some doubts.
Rosie wants to be sure she's making the correct choice.
Rosie sits down with her Fiancee and has a long talk with him about things.
Rosie asks an old casual hookup for one last one night stand, to see if its out of her system.
Rosie's confidence goes through the roof from the reassurances provided.
Rosie's fiancee finds out, and breaks off the marriage, no longer trusting her.