well sounds like either you're just not the settling type or you haven't reached that stage yet. either way don't fuck around when in a relationship because that's just being stupid and immature.
Imo, it's not a real relationship unless there are children. I mean, otherwise it's just two adults who for the moment don't want to have sex with other people. Likewise, why ever get married if not to provide a stable home for the children.
I understand the lust and desire for a new girl very well, but I'm not in a relationship either and won't be in one just for stable sex/security like most. How awesome is it to yet off to another country and meet local honeys?
I suppose people are just different, but the ironic thing is that of the 5 guys I know in my immedeate circle of friends, 2 of them are cheating bastards a 3rd has cheated several times and only 1 is definitely faithfull, but he is a bit of a pussy. None of them are assholes either, just normal guys.
I think that temptation will always be there for men and I also think it's much, much worse when a woman cheats because it will usually mean she isn't in love with you anymore and will likely look to break up, while a man can easily separate sex and emotion.