That Hamilton Woman (1941)

Sir William Hamilton, a widower of mature years, is British ambassador to the Court of Naples. Emma, who comes for a visit with her mother, wouldn't make the grade with London society, but she gets along well with the Queen of Naples. Emma likes being Lady Hamilton, and life goes smoothly until Lord Nelson pays a visit. Sir William decides at first to let his young wife have her fling and pretends not to know what is going on. But the real-life lovers, whose first screen romance was in "Fire Over England" (1937) have an even more burning passion for each other in this movie.