Like Bill, I thought of famous theater couples-- maybe not infamous, but Stiller and Meyer, and Jessica Tandy/Hugh Cronin jump right to mind. And here in NY, Rudy and (pick one) wife or mistress! Its interesting that a "choir boy mayor" whe objects to people jaywalking openly has affairs!

going back in history-- lots of political couples-- Napolean and Josephine, Jenny Jerome and Randolf Churchhill, and Henry VIII and any one of his 6 wifes-- even mousy Jane Seymore is memorable.