The main reasons why men (and women) cheat on their partners are as follows:
They lack sexual satisfaction from their primary relationship. The sex does not meet their needs, their fantasies aren’t being realized, or they aren’t getting the amount of sex they would like, could also be reasons people cheat
They desire additional sexual encounters. Either they want to experience more sexual partners or just more sex in general could be a reasons people cheat
They lack emotional satisfaction from their primary relationship. They either don’t feel a strong emotional connection to their partner, or that emotional connection is lacking in some way.
They want emotional validation from someone else. Either they aren’t getting the praise, respect, and validation that they need from their partner, or they are but they want even more of it.
They have falling (or are falling) out of love with their primary partner. The relationship is basically over, so they don’t feel a need to stay committed will definitely be a reasons people cheat
They have fallen (or are falling) in love with someone new. Either they met someone and things just happened or they had a crush which they actively pursued. Either way, they have developed feelings for a new person, and instead of resisting temptation, they decided to follow their desires.
They want to seek revenge. Either they are seeking revenge for another affair, or simply for a different infraction that they feel their partner perpetrated against them. This could be real or imagined which leads to reasons people cheat
They’re curious and want to experience new things. Either they feel like they haven’t experienced enough out of life, or they want to experience something that is “against the rules,” or they simply want to see what it would be like to spend the night with that one person. They’re just in it to satisfy their curiosity or experience a thrill.
It should be noted, that cheating is not a male-only habit. According to studies, about 70% of women, and about 72% of men, have cheated on a romantic partner at some point in their lives.
However, that romantic partner is usually a dating partner. Only about 25% of people have had an extra-marital affair.