It seems that there are many varying degrees of perception regarding what constitutes "cheating". I know women who have done everything but have intercourse w/ another man whilst married, but since they can still technically say they haven't "had sex" with another man, they don't carry the burden of guilt. This is of course a play on semantics, Clinton style, but I find there to be an apparant trend with this mentality.
Some say sex constitutes cheating (yes, there are many people in this world who actually enjoy watching their other have sex with another), some say kissing is cheating, some even say the very nature of diverted thought (from your loved one) constitutes cheating.
Would you consider your wife fanatasizing about another man, cheating? Is the threshold of cheating emotional, physical, or both? I'd say men more readily disregard their fantasies as innocent, whilst they would consider the female analog to be more taboo, and less acceptable. A bit of a double standard.