Infidelity is not just about sex outside the relationship, but about trust, betrayal lying and disloyalty.
Sexual infidelity in marriage is called adultery, philandery or an affair and in other interpersonal relationships it may be called cheating. A man whose wife has committed adultery is referred to as a cuckold, but no equivalent word exists for a woman whose partner has cheated.
Stolen Kisses [2] Studies suggest that around 30% to 40% of dating relationships and 40% to 60% of marriages are marked by at least one incident of sexual infidelity. Men are more likely than women to have a sexual affair, regardless of whether or not they are in a married or dating relationship. Close encounters: Communication in relationships.Guerrero , L.K. , Anderson, P.A. , & Afifi, W.A. (2007).Sage Publications.
Some people consider virtual sex, which is an on-line relationship, as infidelity.
These include: opportunistic infidelity, obligatory infidelity, romantic infidelity, conflicted romantic infidelity, and commemorative infidelity. Opportunistic infidelity occurs when a partner is in love and attached to a spouse, but surrenders to their sexual desire for someone else. This is driven by situational circumstances or opportunity and risk-taking behavior. Obligatory infidelity is based on fear, a fear that refraining from someones sexual advances will result in rejection. Some people end up cheating solely on the need for approval, even though they may still hold a strong attraction to their spouse. Romantic infidelity occurs when the cheater is, so to speak, falling out of love with his/her spouse. Their commitment to the marriage is what is most likely keeping them with their spouse. Conflicted romantic infidelity takes place when a person falls in love and has a strong sexual desire for multiple people at one time. Although there is the idea of one true love, it is possible to have a strong love attraction to more than one person at the same time. Commemorative infidelity occurs when a person has completely fell out of love with their spouse, but is still in a committed relationship with them. These are all categories and reason to which a spouse would cheat or have the notion to do so. Meyer, Cathy. "Types of Infidelity." About . 30 Mar 2009.
Source: Wikipedia > Infidelity
What is QuickyWiki? QuickyWiki blends the depth of Wikipedia with the ease and speed of Cliffs Notes.