有配偶的男人包养与之以夫妻形式共同生活的别的女子to keep a mistress

• 现在我国实行严格的一夫一妻制，“包二奶”只好是偷偷摸摸的。

  At present China has a strict policy of monogamy; those who keep mistresses must do so secretly.

• 当地官员养情妇、包二奶已经相当严重。

  The situation of local officials keeping mistresses and even second wives has become a serious problem.