People is reporting that David Letterman previously had a sexual relationship with another employee in the 1990s. This follows the details that emerged today about the extortion plot Letterman announced on his show last night. A former Late Show with David Letterman staffer told People that this relationship was prior to Stephanie Birkitt joining the show and was with a different female staff member. Letterman was unmarried at the time and the source told People: “He never acted inappropriate with any of the female staff.”