Killah, not to put to fine of a point on it, but there is a HELLUVA difference between flirting and fucking, flirting does not automatically lead to cheating.
Flirting is acknowledgement of another person's sexuality, but it doesn't mean you're going to act on it. It's nearly impossible to sanitize male/female interaction, and it's unreasonable to try.
My ex had his black and white rules, hell, he took it a step further and extended it to porn, erotica, oh, and yes, those true bugaboos of all relationships, masturbation and even sex dreams. He was a jealous, possessive son of a bitch and that was a small part of what destroyed our relationship (his insanity pretty well screwed up the rest).
My current husband and I don't buy into the jealousy routine. When you're jealous, you're insecure which makes you want to try to possess and control the other person. Unreasonable. Maybe it takes being older or being in a secure relationship or something else, but if we were in a social situation and I saw my husband being flirtatious with another woman ... he's just being a flirt, I met him he was a flirt, he's always been a flirt. His father was a flirt! At the end of the day he comes home with me and I have no fears of him plowing another woman's field ...