The most obvious reason why men cheat is when they are far from God; in the sense that the carnal mind takes over.
Now the following are all based on a Godlessness life:
1. When our personalities don't match. For example you don't like going out but I do. The day I find a girl who does I will definitely cheat on you knowingly or unknowingly.
2. Boredom: when I am bored with you, anything that will bring me excitement, I will do, including cheating.
3. Man's nature: naturally men are attracted to ladies, that is even if he is married. They would always look and be tempted. And whenever the opportunity presents itself I will jump on her.
4. I can cheat in order to come out of a bad situation. For example I can sleep with my boss if need be in order to maintain my job
5. I can cheat when my partner no longer takes care of her body. That means she neglects herself or simply put, if she loses her sexiness
6. If my partner doesn't satisfy me I will most likely look elsewhere.
7. If my partner stresses me continuously, wherever I can get a bit of comfort, even if it’s from an ugly lady, I will be with her.
8. Distance: when my partner is away, especially for a long while, that can also push me to cheat on her. After all she is far and she won't know (we think).
9. Peer pressure. In the sense that everyone (all my friends) are doing it, so why not me. Or my friends can even push me to do it.
10. We also only live once, so let me enjoy as much as possible by sleeping around with as many girls as possible.
11. Wanting to make up for your innocent days where you clearly had enough chances to sleep around but you didn't. And now you decide it is time to do it all
12. You may want to cheat also just because you’ve disagreed with your partner. Maybe after she has annoyed me so much or during a separation. This kind of cheating is basically out of anger or emotional pain caused by the partner.