Uxoricide is a fancy way to talk about a man murdering his wife. Some people believe that O.J. Simpson is guilty of uxoricide, though he was acquitted in a criminal trial.
Through history, there have been many men either guilty or suspected of uxoricide, including England's King Henry VIII, who had two of his wives executed, and the Roman Emperor Nero, who reportedly also killed two wives. You can use this impressive word for both the act of murder or the murderer himself. It comes from the Latin roots uxor, "wife," and cida, "cutter, killer, or slayer."