King Henry VIII is known for having six wives in his obsessive quest for legitimate male heirs. But Henry wasn't the only King in history to have this problem. While no one in Western Europe quite managed to top his total of six, there were a few kings that married multiple times before they got the desired heir, and occasionally a spare.
King Philip II of Spain was married a total of four times. His second marriage is quite well known in British history, as his wife was Queen Mary I of England. But before Mary and after her there were several women to whom he was married, and three of them were related to him, one way or another.