Uxoricide is the murder of a wife by her spouse. The word also refers to the spouse who commits that crime.
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 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."