What causes cheating or sexual infidelity?

Cheating is a symptom that something is missing. Usually the unfaithful partner is feeling: 1) the loss of romance,sex,& excitement. It is easier to fall in love than to stay in love; 2) the lack of connection and communication including the difficulty discussing touchy subjects like money, sex, & in-laws causing emotional distance between partners; 3) wavering self-acceptance and self-esteem causing the unfaithful partner to seek approval, admiration, and esteem from other people. The unfaithful partner may feel superior or inferior to others, neither of which is reliable self-esteem. Affairs typically start through an emotional connection which leads to the sexual relationship.