Some reasons that men cheat are for emotional satisfaction and because men have unrealistic expectations about their partners. Some men cheat because they have addictions that cloud good judgment. Other men want to end the relationship and hope to use the affair as the catalyst.
Cheating for emotional satisfaction can encompass a wide variety of reasons for cheating, including a desire to feel valued by a woman. If a man feels that his partner does not offer him enough affirmation about his ability to provide, or if another woman constantly shows him affection and strokes his ego, the man might cheat for emotional reasons. Similarly, a man's insecurity can lead to cheating because the man wants to prove to himself that he is sexually desirable.
A man that is overworked or bored might use these personal problems to justify an affair. A narcissistic man expects his partner to satisfy his every physical and emotional need. When the man's partner inevitably can't meet his every need, he uses the woman's supposed failings to justify an affair.
Addictions to drugs or alcohol or impulse-control problems can lead to cheating. These problems often cloud good judgment. Cheating can result as a form of self-treatment for addiction, or cheating can occur simply because the man cannot rationalize decisions in a normal way.
A man might use an affair to send his partner a message that he wants to end the relationship. If a man is emotionally dependent, he might choose to begin a new relationship through an affair before ending his current relationship to satisfy his own emotionally-dependent needs.