I believe that Margaery is a) a virgin b ) is way too canny and clever to be promiscuous when she is under the microscope in that pit of vipers and c) was attempting to get Moon Tea for her cousin Elinor who was betrothed to a handsome squire. I just think there was a narrative reason why they keep referring to them.   In fact, I have developed a theory that while Elinor was betrothed to her nice Ambrose boy, she was secretly deflowered and knocked up by the Bastard of Driftmark, hence