Infidelity

In a religious context, infidelity is lack of the faith that a religion requires; one who lacks such faith is an infidel.

According to recent usages, infidelity or unfaithfulness usually means failure to fulfill a tacit or explicit sexual commitment, usually to monogamy, although in polyamorous relationships the commitment is generally to the group.

Different couples (or groups) -- and even different individuals -- may have different ideas of what constitutes infidelity. For example, a person may not want his or her partner flirting with anyone else, may accept that but draw the line at petting, may be comfortable with anything short of sexual intercourse, or something in between; additionally, a heterosexual may accept his or her partner engaging in homosexual but not heterosexual acts with others, or vice versa.

Infidelity within marriage is often called "adultery."

Compare fidelity, faithfulness