One more wife he could have who solves a lot of problems is Jeyne Arryn. For different reasons. 1: The death of Aemma Arryn, there, you already solved this but, her death was a problem for many reasons, not only for the Targaryens but for the Arryns, you have to realize that Aemma was the youngest daughter of Rodrik Arryn former lord of the Griffon and hand of the king of Jaeherys I and his daughters and sons died very young, along with what is known the closest baronial cousins leaving Jeyne Arryn alone but she at least had Aemma to protect her when Aemma died She would lose this protection and others with certain claims would begin to come out. In total, this time she has a powerful aunt who supports her and with her Viserys. 2 The problem called Daemon his constant insults to the Valley and his wife did not win Jeyne love since being Rhaenyra's cousin and marrying an enemy Dameon apart from the houses of the Valley. 3 His marriage to her would be very useful for several reasons. - First, I would give Jeyne legitimacy since a husband with dragons would intimidate most of his enemies. And his children would be more or less the same or they are riders of Great Eagles like his ancestor Artys Arryn. - would repair the ties between Targ and Arryn since Nyra and Jeyne would be cousins-wives. -It would be the beginning of the Valyrios-Andalus Alliance. Since the Arryn were the Kings of All Andals. That would mean that the Faith would not dare deny this marriage since the Arryns were the first King House of the Andals and The Seven.