Hmm. There's a lot to chew on in this thread, and the other cheating thread as well. I hate to reiterate the points that other posters have made, but cheating truly is subjective, just as are relationship rules, boundaries, etc. What is good for one couple might not be so good for another. I respect that some people have different ideas of cheating, as long as devious tactics aren't employed, such as hiding the truth, or outright lying, I'm cool with it. My own personal beliefs on the cheating issue? Flirting, within reason, is perfectly acceptable. Talk is talk. With me, when flirted with by a friend, I flirt back mainly because I gotta have the last word. I like to word-spar, in a light-hearted kinda way. My boyfriend does the same, but neither of us would ever say anything over the top. Physical contact, aside a friendly hug and/or kiss when meeting up with a friend or family member, is not allowed. My boyfriend kissing (and beyond) another woman in a sexual manner would not be acceptable, and he feels the same way about me. We both were very clear on what the limits are and luckily we both see eye to eye on the issue.
Like anything else, though, to each his or her own.