Meh, only women I flirt with that I'm not actually trying to sleep with are friends, and then really the flirting is in a joking manner. Alot of female friends do it as they like the attention, or makes them feel attractive. We're doing it for different reasons. My reasons tend to become "bad, cheating things" (as flirting, real flirting, for me would never come to any fulfillment) and I lose out on something whereas you get to keep your enjoyments. Personally cheating to me is something done behind anothers back without their knowledge. An open relationship is something that is just that open. Things of a physical nature I dont considered cheating if they've been earmarked as "ok" by both parties. It's the emotional side of things I view as important in a relationship ie If I have to go put my dog down are you going to be available for some support, will that someone be around to help celebrate a triumph? And of course vice versa. I dont view sex as something solely intimate, there are intimate things within the act, but not in and of itself - I think alot of people bundle it all up as intimacy (for me a passionate emotional kiss can be much more cheating than 3 hours of sport fucking). I dont require open or a monogamous relationship one way or the other, I just require "ground rules" be fairly evident and they be equal.
As for that BS of someone allowing his mate to have sex with another being weak, and a man's primal nature should take over. You do realize that if you cant control your "base/primal instincts" (btw you cant convince me these aren't looooooong gone through evolution making them no longer necessary) you are actually the weak one as you dont have the strength of will to be logical/rational over an issue and immediatly drop into a purely emotional response. Personally if my physical needs are met, my emotional needs are met, (of course I'm saying these are provided for her as well), I'm afforded the same luxury, and we both prefer that a good portion of the time we choose with other people is spent with each other; then if sexual freedom is something she desires I've no problem with her having it. I'm secure enough in my manhood, my physical nature, my mental nature, and my emotional nature to deal with it or walk away if the situation becomes something that isn't working. So which is it, are you weak willed and unable to control your "baser nature" or are you just insecure in yourself?