Can not see how jiang xuanbao ever got to be a left or right chancellor, he is too gullible and stupid, believes anything almost anyone says especially his wife. Since there are so many incidents in his family occurring and he doesn’t question anything. Obviously really doesn’t care about his daughter(s) just his reputation and how he looks to others. The grandmother is too passive and must not feel she has any real power either. Pretty much the same with the emperor, doesn’t may sense how she betrayed her brother to help the present emperor ascend to the throne, so she can have a lot of power in the palace
Lastly the ex-husband is probably more unscrupulous than Princess Wanning once he learnt to deal with her, had the nerve to be jealous of his former wife, after the other things he did, he just as crazy as the princess they deserved each other