Compton was showered with gifts from the king, and became one of the wealthiest men at court. He was given Fulbroke Castle - which later became Compton Wynates, the family home. He was a gentle, soft-spoken man and was well-liked at court. Really, looking at all of Compton's traits, it seems he had it all. Therefore, it's really no surprise that he gained the admiration of a beautiful lady at court, and sister to the traitor, the Duke of Buckingham, Lady Anne Hastings (previously "Stafford" before her marriage to George Hastings). She was roughly the same age as William when they met, but by that point she was already married for the second time to Lord Hastings. Anne was a mistress of King Henry VIII starting around 1510 - a year or so into her marriage. The go-between man, most likely, was Compton, who probably brought Anne to the King's chambers and passed along messages and gifts between them.
Here is a picture of Compton Wynates, where the Compton family still lives to this day! King Henry VIII's coat of arms are still visible in the stained-glass window of the bedroom he would stay in when visiting.