The Tudors - Season 4 Episode 4 Natural Ally It's Good to Be King.
Overview: Rejuvenated by his tour of the north of England, Henry feels a new man and longs after his new Queen; unaware that her affections are diverted elsewhere. Katherine’s past begins to catch up as an old liaison comes looking for a job threatening to reveal all about their sexual history. Someone beats him to it when an anonymous letter is sent to the King containing accusations of adultery. Although unconvinced of the rumor, Henry confines Katherine to her apartments pending a thorough investigation.