Madam Gu is somewhat jealous of her sister-in-law, as men in the Great Qing often have many wives and concubines, even the Duke Zhongyong has two concubines and maidservants, yet Gu Xiangyi does not.
This sister-in-law has been married for nearly twenty years, and her husband, Song Zhiyuan, hasn't taken a single concubine. Even when she was pregnant and gave birth, he didn't bring in a maidservant to serve him in bed.
In the past, it was understandable that Song Zhiyuan, with no power or influence, wouldn't dare to take concubines because of the power of the Duke Zhongyong Mansion. But later, as Song Zhiyuan's position grew, he remained consistent.
Now, having risen to the high rank of Prime Minister's Mansion, he still remains devoted to Gu Xiangyi alone. How could that not make others jealous?
Not only is Madam Gu herself envious, but many women in the capital are jealous of her as well.