There was a story I read a while back that I believe was on this very site, but it may have been lost in the crash and I can't for the life of me remember what it was called. What I do know is that it started with a husband giving his wife a necklace, which had an inscription that I think was in latin basically warning not to cheat on your significant other, which she is doing. However, while on a date with her other lover, the necklace begins to react and magically mental regresses her, as well as alter her clothes to match.