unfaithfulness
n. 不忠实；不信守婚誓
例句
He was living a secret life of deceit and unfaithfulness.
他过着欺骗和不忠的隐瞒生活。
《柯林斯英汉双解大词典》
They are very revengeful and slow to forgive infidelity and unfaithfulness in love.
他们报复心重，对爱情中的背叛和不忠不易原谅。
The people of Judah were taken captive to Babylon because of their unfaithfulness.
犹大人因犯罪就被掳到巴比伦。
