I have mixed feelings about this. Someone I know was engaged as well and this guy from 4 years back came back into her life and guess what happened.... they ended up being back together and she left that guy she's engaged to. It's happened to a lot of people that I know. Unless you are ready to stir the pot and you can't contain yourself then tell him. but if these were feelings from the past and you don't feel the same about him... then you shouldn't say anything.

Also, if you were in his situation and your fiancee's old time crush came along a year before you were to get married, wouldn't you feel a little uneasy. Ijust tend to base things on how others feel before I act or react to something.