He Knew He Was Right is an 1869 novel written by Anthony Trollope which describes the failure of a marriage caused by the unreasonable jealousy of a husband worsened by the stubbornness of a willful wife. A wealthy young English gentleman, Louis Trevelyan, visits the fictional Mandarin Islands, and becomes infatuated with Emily Rowley, the eldest daughter of the governor, Sir Marmaduke Rowley. The Rowleys accompany Trevelyan to London, where he marries Emily. The marriage is initially a happy one and the couple have a baby boy. Then a seemingly minor matter undermines their marriage. Colonel Osborne, an old friend of Sir Marmaduke's, visits Emily much too frequently for her husband's taste. Though nothing improper occurs, Trevelyan orders his wife to avoid the man in future. Emily resents his lack of trust and does not attempt to hide it. Their relationship deteriorates to the point that they separate…