He had no son. Henry feared that his daughter Mary would not be acceptable as sovereign, since there had never been a female ruler of England.
He believed that his lack of a son was a punishment from God because he had married his brother’s wife.
A text in the Old Testament, in the Book of Leviticus, claimed that such a marriage was unlawful in the sight of God.
For Henry, it became a matter of conscience. He had sinned against God and must now atone.
Henry believed that Popes did not have the power to allow a marriage such as his with his own sister-in law. Therefore, he had never been married to her in the sight of God.
Henry was very much attracted to Anne Boleyn. He wanted to marry her and produce a male heir.