According to Targaryan custom, then, he should marry Danaerys!
Okay, on another subject--we all see the parallels with the Wars of the Roses, right? Consider some of the characters and how they correlate...
Edward IV = brilliant warlord and general who didn't know what to do with himself in peace, fell to drinking and womanizing. Eldest of three surviving brothers. Robert Barantheon yes?
Richard of York = leader of one side, who balked at the last moment from seizing the throne from Henry VI and thus condemned himself and one of his sons ultimately to death. Ned Stark.
Queen Margaret of Anjou = cruel, strong, fanatically devoted to her son. Cersei?
Earl of Warwick, the Kingmaker = wealthiest man in the realm, given to schemes and ruthless use of his own children as pawns. Tywin Lannister.
Richard III = third of a set of royal siblings, deformed and so despised. Okay do we really need to mention who this is?
It isn't one-on-one though. For example, Richard III wasn't really interested in women but only in power ("Love foreswore me in my mother's womb"). More, while brilliant at getting the throne had no notion at all (at least in Shakespeare's play) of what to do with it. He made a terrible king for that reason. Reminds me of Cersei, honestly. The real Richard Gloster, on the other hand, comes across as more like Ned Stark--a dour individual devoted to his friends and family, betrayed in the end by other lords. He was even called the "Lord of the North"!