He was living a secret life of deceit and unfaithfulness.

他过着欺骗和不忠的隐瞒生活。

His unfaithfulness had certainly broken her heart.

他的背叛势必深深伤了她的心。

I am catching evidence for the man's unfaithfulness to his wife.

我正在收集那个男人不忠的证据。

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。