What Does The Trollope Title "He Knew He Was Right"� Refer To?

This 1869 novel, which has also been adapted for the BBC, describes the marriage of Louis Trevelyan and Emily Rowley, daughter of the governor of the Mandarin Islands. Brought up in a freer atmosphere, Emily has trouble adjusting to the conventions of her new English home. Matters come to a head when her father's friend, middle-aged ladies' man Colonel Osborne, comes to England and starts visiting her. He has known Emily since her childhood and his visits are perfectly innocent, so when Louis demands that she stop seeing him, she refuses. Louis becomes insanely jealous; the couple later separate, and he even employs a private detective to spy on her. Eventually Louis kidnaps their son and takes him to Italy, where he has a complete breakdown. Emily later finds him there and tries to nurse him back to health, but although the couple are partly reconciled it is too late, and Louis dies without ever admitting that he was wrong.