Who is Maxwell from Wieland; and Memoirs of Carwin the Biloquist and what is their importance?

Maxwell seduced Major Stuart's wife as a way to get back at Stuart, causing Mrs. Stuart to flee to America with her daughter Louisa. When Stuart finally learns the truth, he confronts Maxwell and challenges him to a duel. Unfrotunately, Stuart is murdered before the duel takes place. Maxwell is a prime suspect in Stuart's murder.