I never understood why after a man cheats on his wife, the first thing people point out is that the wife is hotter than the girl the man cheated with as if cheating is all about physical attraction. It implies, although you don't mean this, that if the girl WAS hotter, that you can understand the decision and it's less bad. I think men who cheat don't cheat because their wife doesn't look good enough. It's more that the wife isn't providing something that the man wants, whether that be excitement, spontaneity, an ear to listen, etc. Sexual satisfaction doesn't depend on looks all the time. We all know that hot girls can be terrible in bed.
Now, here's a better corny joke:
Bumper sticker: "Don't call me Tiger...Call me Cheetah!"