The one talking is another Duke. Yeah, he does mean that Duke Trude (idr sp lol) has been sleeping with some of the Regas, and that the ones the Duke does sleep with all look like the King's...most favored ig (since atm Regas is more or less synonymous to harem with the current king).
Wait I don’t get the last chapter. Does the king mean that the Duke has been sleeping with some of the Kings regas ?