I don't think a little flirting is bad. I actually like when other women check out my husband. I get a few kicks out of flirting myself. Fantasizing (to a degree) about celebrities or porn women is ok. Fantasizing about real women isn't. Checking out another woman in my presence is ok. Embarassing me by rubbernecking her all down the street isn't. I guess a playful drunken kiss can be considered ok, but even a tongue-less kiss can be considered cheating if he has a "cheatin' heart".
yeah i read an article once about how u can kind of have an 'emotional affair' because even though you arent doing anything with them you still have feelings for them, but then you cant really help your feelings can you? the same article also talked about how you could be in love with more than one person, because they are different types of love, so i guess everyone has to form their own opinion on what is cheating and what isnt