I think most people get tempted. You just need good boundaries. If you are attracted then you do not spend time alone with that person, you do not flirt or share intimate conversations. If you do not get out on the ledge, you cannot fall of the ledge.
As some others have said, I can admire an attractive woman ("Sharon" on the newer TV series Battlestar Gallactica is HOT), but I have no interest or temptation to do physical things with someone other than my partner. I've done my share of experimentation in the past, and am now very happy being monogamous.
Do you ever feel tempted towards other people even while being married?
I think it's natural to be attracted to others even when you're in a commited relationship of any kind. The key is to not act on those urges (unless that is something you and your partner are okay with and have set up parameters for...)