ROBERT WALKER
But his wife, Jennifer Jones (with whom he had two young children), began having an affair with producer David O. Selznick in 1943, and two years later the affair became publicly known and they separated, and his heart was broken and he became a major alcoholic, and his career suffered greatly (meanwhile, Selznick dumped his wife and married Jones).
In 1951 he made a great comeback as the crazy murderous Bruno in Hitchcock's Strangers On a Train, but he passed away the year it was released, after an accidental overdose of drugs and alcohol. Walker was 32 years old. He gave a quote that accurately summed up the tragedy of his life: "My personal life has been completely wrecked by David Selznick's obsession for my wife. What can you do to fight such a powerful man?"