Yī zhāng chuáng shàng shuō bù chū liǎngyàng huà.

一張床上說不出兩樣話。

Lit [A couple] sharing one bed won't speak two different languages.

Fig Husband and wife (should) always present a “united front” to those outside the family.

Note [See also yī jiā rén bù shuō below.]

Topics COUPLES HUSBANDS UNITY WIVES