Not all guys just want girls for sex. But instinct is still something that really bothers you at times like these, men just can't resist it in most of times... And even when you know that you love someone, when something as this comes to you, it can be really annoying.
At least part of that is biology/instinct, for most of the history of our species (and still today in large part) if a man got a woman pregnant and didn't want to raise the baby he could just leave. The woman doesn't have that option, she's stuck at least until she has the baby or has a miscarriage/abortion. So women might have a stronger tendency to be monogamous and selective of their partners purely on instinct.
Yes but again how do you define cheating? Is it a violation of trust? Does it have to be a physical act? I'm not a religious man by any stretch of the imagination however in Matthew 5:28 Jesus says "But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart."*
So are lustful thoughts for those who are not your partner infidelity? Or does a perhaps older axiom hold true, that being "I'm married, not dead." ?
About the first one, what do you mean with "instinct" in there, Ratty? And, you're not relating emotions to it as well, are you?
And about the second one, i know what you mean. So even if a man really loves a person, he can still be with another girls and that's it? I don't know, i think there's more than just one thing to think about.
First, what is he feeling for both girls? Is this really love? Or maybe what he feels for the second one is lust?
Second, as you said, what is considered infidelity? Even if he could feel the same for both girls, or not, so just staying with a second girl as well is enough to be considered cheating?
And third, isn't it wrong? I mean, can he still live with both at the same time? Even if he loves one person only, is it still okay to live with more than just one? Maybe? Since one of them agrees with that and doesn't see it as cheating? I think it's not just the opinion of the man that counts, but the opinion of each girl as well, don't you agree with it? So they can all live in harmony, even if in a three-person relationship or whatever that is.. I don't mean to relate it to the religious point of view, though..