She was a young widowed queen and you are the only one she trusts to keep her safe as one of the former king's most trusted knights/advisers. The queen didn't expect him to come running into her bed chamber sword drawn, she hadn't realized how loud she had screamed as she pleasured herself. (Would want to play the queen)
Would also be up for playing this as a slash line against the late teens prince who is now king and the knight/adviser.