That there was NO divorce till Henry VIII is not really accurate.
Divorces were routine among the nobility and especially royalty, bought and paid for to the pope. Papal dispensation, sudden discovery of invalidating degree of kinship, etc. Part of Henry’s outrage at being denied on by the pope is that they were so common for kings.
Elanor of Aquitane, for instance, divorced the King of France and married the King of England.
If I remember correctly, the Pope even provided a dispensation for one Emperor to commit bigamy.
The pope in Henry’s case probably did not develop a sudden rush of integrity to the brain. He was a prisoner of the Emperor, a nephew of Catharine, and simply wasn’t free to gratify Henry.