"She was intending on letting Sun Guohong support her entire family, including her, her husband, and their children."
But what that woman had not expected was that Mother Sun was even more scheming than she was! Mother Sun already had her eyes on the secretary's daughter as her younger daughter-in-law.
Unfortunately, when Sun Guoming and the secretary's daughter got engaged, she was already Sun Guoming's woman. Since that was a fact that could not be altered, that woman chose to stay with Sun Guoming. That way, Mother Sun would take better care of her too. She even had a joke whenever she saw Mother Sun. After all, Sun Guoming was Mother Sun's favorite son, and he even constantly reminded Mother Sun that Yanyan was a good young lady.
It was not until Yanyan got pregnant with Sun Guoming's child did Mother Sun find out about the relationship between her elder daughter-in-law and her younger son.