In 1926, Ernest Hemingway left his first wife (Hadley Richardson) and their small son for a wealthy writer named Pauline Pfeiffer. Shortly thereafter, Hemingway was asked why he had left. His reply? "Because I am a bastard."
[According to some biographers, Hemingway had another reason: Hadley was an airhead. She once took the train from their apartment in Paris to visit Hemingway in Switzerland, brought along a suitcase full of his work-in-progress (at his request), and had it stolen on the train. (The incident, recounted in Nicholas Delbanco's The Lost Suitcase, was devastating for both of them as well as for their marriage.) On the other hand, Hemingway was indeed a bastard: Pfeiffer was soon ditched for journalist Martha Gellhorn (wife number three), who in turn was pitched for Mary Welsh (wife number four)...]
[One of Ernest Hemingway's sisters married her fiancee over his objections. He never spoke to her again.]