Just read a chapter of Osamu Tezuka's Black Jack the other day pertaining to the topic at hand...
Black Jack's father summoned him to aid in fixing his wife's disfigured face. At this part, we already know that Black Jack's father cheated on his mother, divorced, and ran off when he was a small child and his mother died when he was still very young. As requested (in return for the typical illegally high sum of money), Black Jack fixed his father's wife's disfigured face. After time passed, the bandages were removed and she had the face of Black Jack's deceased mother. Using same word over and over again doesn't feel right but their names were never given.
Thought it was a nice story and on the topic at hand, I thought I'd share it. Now as for my opinion on cheating, I don't agree with it, I don't agree with divorce either. Don't jump into a deep relationship on whim, think over what that person means to you, think of what this bond will lead to. If you have the urge to cheat on your spouse, think things over like what the end of your marriage would lead to and if you truly love them. If you don't love your spouse, by all means, tell them but try to be gentle when doing so and after your divorce, by all means, try to find someone new.
Still, I pray I hit the mark right with my first girlfriend. What? My father did so with my mother and if so, why can't I?