The concept of marriage is so different between US and China. Chinese don't divorce easily. They consider it a shame. Especially after they have children, they will continue to live together as a whole for their children no matter what..
I would guess the main reason CHionese women stay in a marriage where there husband has a mistress is becuase of the children. Divorce laws in the US are more favorable to the woman than in China so women are more likely to divorce in the US if a man cheats.
I know a Tawanese lady who told me that custody of the children is usually granted to the father in Taiwan qnd this prevents women from divorcing. Is the same way in China?