in·fi·del·i·ty 
/ˌɪnfəˈdɛləti/ noun
plural in·fi·del·i·ties /ˌɪnfəˈdɛləti/ noun : the act or fact of having a romantic or sexual relationship with someone other than your husband, wife, or partner [noncount] ▪ She was convinced that her husband was guilty of infidelity. [count] ▪ He has admitted to a number of marital infidelities.
