1) A sense of entitlement: There is an under-the-radar behavior, and sometimes blatant sense, that some men/women have that cheating is an entitlement. If they are propositioned or in a seductive situation, they will not say no. It is their right to take advantage. They might even feel that spouses should understand.
2) It could be genetic, such as a grandfather and/or father who committed infidelity. In that case, one learns it is a normal way to function.
3) There is the excitement of being bad; Risk and recklessness make a kind of excitement that many cheaters like. It might momentarily take them out of the doldrums they experience from a quiet, content life. Sometimes, the guilt might make one feel worse than they did before, but not always.
4) The power of feeling manly or a woman seeing desire in a person, other than a partner, might follow through. For some, it adds spice to the everyday grind of living. Men might feel that if they attract a women, it pumps up their masculinity. Women might need a deep need feel desired when their lives have become routine, something unacceptable to them.
5) Men who have been say, captain of the football team or women who have been prom queens, find that once the adoration stops with adulthood, they can only revive that feeling of being adored by cheating. That makes them feel that there are men or women still hungering for them. It gives them a superficial sense they are at the top of their game.
6) There is the power to be felt by merely attracting the opposite sex. Sometimes people feel a lack of self-worth. They find serial cheating injects an artificial sense of superiority. But when it ends, they are at a loss and might seek another conquest to pump their egos up.
7) There may be a crisis in someone’s life; That person might be unable to emotionally handle that crisis — a sick child, a depressed spouse, losing a job, or unsatisfactory careers. Whatever it may be. for them, the only way to deflect that pain is by being a cheat and momentarily taking themselves out of reality. For a short time, it takes them out of the emotional abyss. Not uncommonly, it becomes an addiction and they must continue to cheat to keep that upbeat mood continuing.
8) Sexual addiction may also be a driving force in serial cheating. That might happen for any of the above reasons. Many people in high positions may stay married but find the thrill of sex addictive because it provides a lack of commitment in their promiscuous behavior. Someone told me that sex with prostitutes means you don’t have to say goodbye.
9) There are people in need of unconditional adoration and might experience it in courtship. Once elements like children, buying a home, changing jobs, losing a promotion, etc. might instigate a deep insecurity in certain people. They yearn for unconditional adoration to lessen the burdens. In a few hours a week, they escape these responsibilities.
10) Profound insecurity where a person finds temporary erasure of low self-worth by being desired sexually. Since it may lessen the pain temporarily, they become obsessed with sex and seek it over and over so they don’t have to confront those bad feelings. It raises their sense of importance.
11) Another reason for serial cheating is an lack of maturity. There is an IQ of intelligence and an EQ of emotional growth, that I believe in. For whatever reason, emotional growth can be halted at a young or pre-teen/teen ages and may become a driving force in adulthood. This hindrance to maturity, may turn into a dependent personality, someone who thinks an intimate partner can make them happy. No such thing. We can only make ourselves happy. They develop an overblown sense of their prowess in order to deny their lack of responsible growth. It may manifest into obsessive sexual needs, and they have to keep repeating those behaviors to feed their self-delusions.
12) Finally, the worst and most horrible reasons for cheating, come in the form of a sociopath. These people have no boundaries or empathy except when it comes to themselves. They lack a conscience which makes them feel they are the most important person in the universe and are desired as a result. They have no concern for the feeling of those they hurt.