Technically, he annulled three of his marriages. One of those he beheaded; and he beheaded another while still married to her.
I know he was seeking an annulment of his marriage to Catherine of Aragon, but I think people commonly spoke of it as a divorce. He decided that Anne of Cleves was not as good-looking as her portrait but I don’t know if they had ever consummated the marriage. Who was the third?