Have the Balls to Cheat, Please...

I know the title is a little misleading, but hear me out. I have a problem with cheating, but who doesn't right? Well, some people seem to think it is okay because they do it. I have never understood this though, because if I were no longer interested in the person I am with I would break up with them. I would really like some feed back on this because I don't understand. At the point where you realize that you want to have sex with another person, wouldn't you think that there must be something wrong with your current relationship? There has to be something lacking, something you aren't receiving from your current partner that you feel you have to get it somewhere else. If the cheater could just take a moment to think about this and tell their partner what it is, I am not feeling loved enough or the sex just isnt that good. I think that people should have the respect for their partner enough to be upfront about not being happy. Even if you don't want to tell them why you are leaving (that you want to have sex with someone else) at least just tell them straight up that it is over. I would rather have a guy tell me that it is over, instead of finding out later that he slept with someone else. I can deal with what is in front of my face, but not what is hidden from me. Is it that men/women are scared of that confrontation? They don't know how to say it? I am unsure. Or maybe people just want to have their cake and eat it too. Their current partner provides security or companionship, and they just want to have a physical encounter with another? I still don't agree with this because it is selfish. I am all for being comfortable with your sexuality, sleeping with whomever you deem fit. But, as long as it doesn't hurt anyone emotionally and physically. Unless someone can give me a valid point as to why I shouldn't think this way, and I am open-minded to suggestions, I stand firm on my view point: If you are going to sleep with someone besides your partner, have the balls to end it first.