"Interpreter of Maladies": Robin Wright Penn

Kevin and I went to see The Interpreter last night (one line review: I enjoy any film that allows Nicole Kidman to showcase a new take on playing unapproachable coldness). But seeing her co-star on screen, I wondered to myself, what would have happened had Sean Penn and Madonna stayed together? Would he have still been so humorless? Would she have still become children's author (like like Mariah Carey!)? And would there have been a sequel to Shanghai Surprise?