Boredom in a static, familiar relationship can lead a man or woman to cheat on his spouse or partner. Shine explains that relationships often begin on a high note with much excitement, but that over time, the thrill diminishes when real life sets in. A bored partner might then meet someone new and experience the longed-for rush of adrenaline. Hungry for more, she becomes caught up in feelings of passion and exhilaration and then engages in an affair.

Boosting a bruised or shaky ego inspires people to cheat. Over time, men and women might become insecure about their ability to still be attractive to the opposite sex, particularly as aging sets in. If someone displays interest in a married man or woman, it might make the married person feel better about himself and trigger a desire for more attention and ego stroking. Such a rush leads people to cheat on their partners, whose compliments they might not value.

Cheating on a partner can lead to a vicious cycle of infidelity where both halves of the couple engage in affairs. A woman might cheat to even the score if her man steps out on her, in an attempt to inflict the same pain and suffering that her partner caused her. The Urban Daily reports that a woman might feel the relationship rules she follows are no longer valid if she is cheated on and might start acting accordingly to strike back at her partner.

Lacking emotional connection causes rifts in relationships and can lead to cheating, according to CNN. When a man or woman does not feel able to go to his partner for affection or to discuss a problem, he might seek another emotional outlet in the form of an affair. Also, if she feels unappreciated or stress over things like children and bills causes her to have feelings of inadequacy, she might think another person might make her feel better luring her into an affair to regain self-esteem.