why......

So I just wrote an entry in my journal to get it off my brain and started to read others. And felt so sad for people just starting their journey on separation and learning how someone they trusted betrayed them. So I want to know - why do people cheat. If I found someone else so irresistible, I would end the relationship I was in before I took that step. And if I was at that level, something was wrong in my relationship and I would have been addressing it. So here we go, marching along every day thinking all is good, and WHAM - blindside. So if you have cheated, tell me why. Were you afraid to end it with your partner even though things had to be bad? But not too afraid to cheat? What am I missing? It's a mystery to me. When did you fall out of love but didn't mention it, didn't try to work on it? I know both women and men cheat. I just have a hard time understanding how people are able to risk hurting a person who once meant so much to you. You may not be in the same place you were years ago, but your feeling for them at one time were strong. It's so much much kinder to end the relationship before you cheat - so they only have to deal with that. Knowing the relationship is over and the person you still love found someone else they want more than you is devastating. It hits your heart, your self confidence, almost every part of you. I can't even imagine doing that to someone I once loved and shared my life with. Even if the love was gone. So explain it to me......