In the marriage game, when is it time to throw in the towel? Margot Simpson was raised to believe that you don't run for cover the moment it rains. You don't slide divorce papers across the kitchen island, especially when you have a teenage son. You roll up your sleeves, toss your hair in a bun, and dance in the downpour. When Margot abandoned her singing career on Broadway to follow the man of her dreams to...