What if King Arthur was married to Morgan le Fay

What if King Arthur Married to his half sister Morgan Le Fay, instead of Guinevere?

Morgan would be the first queen to have magic and married to a half brother. Both of them are Mordred's parents which would make him the sole heir to the throne of Camelot.

She and Mordred would not be the villains of the Arthurian Legends.