The End of the Affair (1999)

In the years following World War II, writer Maurice Bendrix (Ralph Fiennes) has an unexpected run-in with Henry Miles (Stephen Rea) and his wife, Sarah (Julianne Moore), with whom he once shared a passionate affair. Henry, who never knew, confides in Maurice that he suspects Sarah of adultery, leading to the hiring of a detective (Ian Hart) to follow her. As Sarah never explained why she called off their affair, Maurice follows the investigation closely, his feelings for her reawakened.