Lauliza: Yes, I might be rigid about this, and I am still young. But I always have been more conservative than my friends when it comes to relationships, they for instance don't see the problem with an open relationship or several people dating each other at once, while I do. Why label it as a relationship when you don't plan on being faithful to your partner? Then you're basically just friends with benefits. Which is fine by me, just call it what it is, then. And yes, I do think the least your partner deserve after being cheated on is getting to know about it, it's up to them how much they let it bother them and whether or not they want to stay together anyways (which many people do. It is simply not acceptable to go behind someone's back like that in a relationship. Relationship are about honesty and trust. I believe that if I was in a relationship and my partner told me he had cheated on me, there's a much greater chance I would stay with him than if he DIDN'T tell me and I found out later. Then the trust is broken, and without trust there's no relationship. If you can't stay faithful, don't be in a relationship. Simple as that. Too many people get in relationships without really considering what it means, which ends in bad break-ups later.

And when it comes to biology: Well, that's too simple. Humans have long since stopped following simply instinct. Socialization and cultivation have long ago made us be able to be in control of our impulses. For most people the natural reaction today would not be to get violent if they felt hurt or their position was threatened. It used to be that it was. There are plenty of things throughout history that people have said is natural/wired into us by biology, such as certain differences between sexes or races which quickly turn out to be cultural/societal and not biological when put to the test. It used to be said for instance that by biology, women were not able to comprehend complex information or understand enough to even vote! Or study, for that matter. Now women are the majority of students in many studies. I don't believe "biology" is a valid excuse, I just think it is an excuse as claiming it is biology it gives you a reason to act on impulses and not feel bad about it.