Why did Henry VIII execute Anne Boleyn?

Officially, he executed her on charges (almost certainly fabricated) of adultery (which, since it involved betraying the King, equaled treason) and witchcraft - which is how he explained Anne's seduction of himself. However, he could have pardoned her and/or divorced her instead of having her beheaded. It would seem that by the time he decided to be rid of her on these trumped-up charges, he truly hated her. He hated her for her harsh tongue (seems, ironically, his former mistress did not take kindly to his extra-marital flirtations) and her failure to give him a male heir.

By the time of Anne's fall from favor, Henry was so expert at executing former friends and relations who crossed him in any way, that it was no considerable stretch for him to kill this woman who he had once loved. Loved enough to defy the Pope, the clergy in England, the courts of Europe, popular sentiment of the English people, his once-beloved Queen, Catherine, and his own daughter, Mary, whom he had doted on. He changed the world and history as we know it, all to marry Anne. Then he tired of her and killed her.

Don't think too harshly of him, however. He did spend a considerable amount of money bringing in an expert from Calais to conduct Anne's beheading with a sWord, instead of a traditional English beheading with an axe! She always did love all things French.