There is an ancient novel where the female protagonist surnamed Xia was abandoned by her husband after three years of marriage. She went to Qi Wang Fu to find her husband and was mistaken for a nanny.

I am not sure of the title of the novel you mentioned. However, I can give you some common plot outlines of ancient novels in the hope that they will be of help to you. In Gu Yan's novels, the female protagonist's surname was Xia and she was often abandoned by her husband. Some novels would even describe the female protagonist's experience of being mistaken for a nanny when she went to Prince Qi's mansion to find her husband. This kind of plot could be adapted into various versions. Some novels would even add other plots and characters such as the heroine's allies, enemies, and so on. However, it should be reminded that the plot of the novel is fictional and should not be used as a reference for reality.