You talk some shit, but you just come of ignorant and young.

It's called having boundaries, smart realistic adults do this. If there's any chance you might fuck your female friend (no matter how small), it's smart to have a boundary, like not hanging out alone, drinking alone in a secluded area, e.g.

If you and your gf want to play Russian roulette by hanging out completely alone with some opposite sex that you find attractive, go for it, but when the star align, like maybe drinking is involved, maybe you confided the negativities of the relationship you're in, and ended up emotionally cheating on your significant other and then end up physically cheating as well.

All the other adults that admit their not 100% perfect and in self-control at all times, who were smart enough to put a boundaries, then you'll freaking get it.