Yeah tell her unless shes some sort of nutter,lol.
You feel guilty because part of you went hell yes ! and you so would have, dont let it worry you its natural, in humans monogomous relationships are not natural anyways. You walked away so your in the clear, so worry not, I know what you mean I got hit on by a quite rediculously hot woman the other day, I said no of course I love my gf to bits, but part of me thought, god yes I so would if I could,lol, its not disrespectful to my gf, its just natural that if a very hot woman wanted a bloke, bloke will always either jump on them or say no, due to the fact they have a gf/wife.
So yeah in short, dont beat yourself up, u did the right thing, if a hot stud went up to your wife, she would react the same way as u, drool abit, think if was single she would, but she would do nothing as shes with u, simple as that.
People dont stop becoming attractive just because your taken.