Henry James 
Path of Duty 

This wickedly ironic story is shorter than most of James’s tales. It concerns three English aristocrats and an unnamed female narrator who is herself a target of the irony. Ambrose Tester is in love with Lady Vandeleur, a married woman as the story opens. Conveniently for the plot, however, her husband soon dies and Ambrose has a decision to make. Should he marry the woman he loves or Jocelind, whom he does not love but has gotten himself engaged to, and who loves him. (Goodreads)