The definition of cheating is (breaking the rules).
Both men and women cheat for the same reasons! Anyone who has ever seen an episode of the TV shows "Cheaters" or "The Maury Povich Show" AKA (You are NOT the father!) can attest to that.
Even lesbians cheat on one another! Cheating is not gender specific.
The goal of any cheater is to hold onto all that is "good" in their primary relationship while addressing their other "needs" on the side.
The cheater has no interest in going through a breakup or messy divorce! She or he is not looking to replace one relationship with another one. They simply want to fill the void of whatever is missing from their primary relationship.
For example lets say a man is married and is sexually frustrated with his wife. Odds are if he is incline to cheat he will use the following logic. My wife is unwilling to have sex as much or in the way that I want it so my options are.
1. File for divorce, move into a studio apartment, pay her alimony, child support, and become a weekend dad.
2. Find someone on the side who is more sexually compatible.
* In the event that he does get caught then he may be (forced) to go through option #1. However if he does not get caught he will have (everything) he feels he needs to be happy between what his wife offers and what the mistress offers him.
No cheater expects to get caught. Therefore it's worth the risk in his mind. Cheaters are gamblers and thrill seekers.