extramarital
adjective uk/ˌek.strəˈmær.ɪ.təl/ us/ˌek.strəˈmer.ə.t̬əl/
婚外（性关系）的
An extramarital sexual relationship is one between a married person and someone who is not their husband or wife.
an extramarital affair 婚外恋
Synonym: extracurricular