1. The Boy Who Cried Wolf except with Mr. Woodhouse always saying that he's sick.
2. Munchausen syndrome by proxy in which Mrs. Allen gives her husband gouty symptoms so he'll take her (& Catherine) to Bath. Does she make his symptoms worse to keep him there? How does Catherine get involved?
3. More of a "that's not a physical illness, that's stress/depression" sort of deal in which the hero of your choice takes a much needed break under doctor's orders, meets the heroine, feels better than he has in years, and decides to abandon his old life.