I've had it where one of the female PCs married the Prince, does that count?
The King had two sons (well, and one daughter, but she was rather young). The elder son was a good man; kind, likable, bright, and just. The younger son was sly, selfish, underhanded, and just downright wicked, though still charismatic enough to put on a civil veneer. The younger son was very, very interested in taking the throne for all the power it would bring. The elder son saw rulership as his duty, but had no particular interest in taking power.
The elder son was also, though only known amongst the family, quite gay. Events proceded in which an agreement was struck - two birds with one stone - the PCs were founding their own kingdom to the north and were seeking political alliance with this country. One of the female PCs married the gay Prince, solidifying the alliance and eliminating any potential issues that might arise later when the King would chose to abdicate the throne to his elder son.