the act of not being faithful to your wife, husband or partner, by having sex with somebody else synonym unfaithfulness(夫妻或伴侣间的)不忠行为;通奸 marital infidelity 对婚姻的不忠诚 She could not forgive his infidelities. 她无法原谅他的不忠行为。 her infidelity to her husband 她对丈夫的不忠 His reputation has been damaged by allegations of marital infidelity. 他被指对婚姻不忠,名誉受到了损害。
Word Originlate Middle English (in the senses ‘lack of faith’ and ‘disloyalty’): from Old French infidelite or Latin infidelitas, from infidelis ‘not faithful’, from in- ‘not’ + fidelis ‘faithful’ (from fides ‘faith’, related to fidere ‘to trust’).