Questions: Break Up & Divorce

Cheating... What do you think? Is it a "mistake"? Is it a bad decision?

My perspective:

I look at it as a series of bad decisions. It was no accident that a person meet another of the opposite sex... Not an accident that the two DECIDE to see each other naked... Not an accident that a vajina was penetrated by a penis. All seem intentional to me. So how is it a mistake? Someone mistakenly went into a room or place where someone (that is not the significant other) else were naked, tripped, fallen and a penis mistakenly penetrates a vajina? Don't seem like a mistake, because if I entered a room wherein a naked person not being my significant other is, I would exit and part my ways. I can honestly say I have never cheated or even flirted with another woman if I am committed to someone. I can not imagine myself cheating, and don't understand the compulsion to do so.

I was confronted with an opportunity of cheating, but nothing happened because I controlled the situation. The only thought in my head was if my fiance cheated on me, I'd rip her f*cking heart out of her chest... and I'd expect the same for myself if I were to cheat on her. What are these people thinking?!?

I was cheated on once, and I caught her in the act, with my roommate while I was in the military 8 years ago. She claimed it were a "mistake"... I laughed, and then scoffed,"So you mistakenly fell on top of him naked and his penis 'mistakenly' went inside of you, right? Get the F*ck out of my face, or I'd kill you where you stand." I ended the relationship that instance. And she gave me back my damn ring too.

However, I want to see what you think... Do you consider it a "mistake" or a "decision" when it comes to cheating?

I want explanations... Explain your answer.