At the close of a season defined by mystery — what happened in the Tower of Joy, how would Cersei get vengeance, would we finally meet Lady Stoneheart? — Game of Thrones used "The Winds of Winter," the record-breaking Season 6 finale, to set up an all-new mystery: the question of who Daenerys will marry.
During possibly the most good-natured "sorry babe, you're dumped!" conversation in the history of the Seven Kingdoms, Dany casually revealed to Daario her intention to marry once she crosses the Summer Sea and returns to Westeros.
To his credit, Daario took this news pretty well. He didn't even throw his wine across the room, which is the very least I would've done. Relive the scene below before we get to speculating about who the lucky (or, depending on your opinion of the House Targaryen, cursed) suitor could be.
Keeping It In The Family With Jon
The most obvious contender for Dany's hand in marriage — a touch too obvious, some might say — is Jon Snow. We're dealing with a song of ice and fire here, and we all know which two characters represents those elements.
If the idea of a marriage (consummated) with your own flesh and blood grosses you out, you clearly don't belong to the House Targaryen. The Targs were essentially far smarter than the other ruling houses in Westerosi history: By marrying within the bloodline, they ensured that their children would all have a legitimate, purely Targaryen claim to the throne. (Not all the Targs married each other, but when they didn't things like the infamous Blackfyre Rebellion happened. Better the devil you know, right?)
In a patrilineal society like Westeros, if a male Targaryen takes a bride from another house, his heir would have (for example) Baratheon blood, thus risking rebellion and presenting a threat to the continued reign of the Targaryens. It may be morally corrupt, but it was also the surest way to keep the throne, and the prime reason Dany's ancestors remained in power for three centuries.
If that's a solid argument for incest, neither Daenerys nor Jon actually knows they're related — theoretically, the only living person who does know is Bran. But what if this intelligence had fallen into more calculating hands?
A Political Alliance With Littlefinger
In the Season 5 episode "Sons of the Harpy," Sansa bitterly recalls the rape of Lyanna Stark by Rhaegar Targaryen. Her audience, Littlefinger, looks impassive, the implication being that he knows more of this story than she (and the rest of the House Stark) do.
That wouldn't exactly be a surprise considering Lord Baelish's vast wealth of knowledge and network of spies and, more importantly, it could also motivate Littlefinger to marry Daenerys himself. That arrangement would be mutually beneficial — he could provide her with the Knights of the Vale, more versed in Westerosi battle than the Unsullied and, breaking with Targaryen tradition, the marriage would dilute the bloodline, giving Littlefinger the opportunity to sabotage the Targaryen claim to the throne from within.
Varys, The Secret Targaryen?
A third possibility: Varys knows the secret of what happened in the Tower of Joy. The only man with an even greater spy network than Littlefinger, Varys might be more inclined to share the secret with Daenerys than keep it from her, if you put any stock in the theory that the Spider is actually a Targaryen himself. That might sound insane, but bear in mind that Varys was castrated in a blood magic ritual, the kind traditionally practiced on those who possess king's blood (as with the burning of Princess Shireen at Winterfell, for instance).
Varys and Littlefinger, old enemies united by knowledge of the same secret, one intending to use it for his gain while the other keeps it hidden for the same purpose, would be a beautifully twisted dynamic as the great game enters the home stretch. It's hard to call a winner in that battle of wits.
There are other candidates, none especially convincing: Daenerys could marry Tyrion (potentially inheriting the bulk of the Lannister army in the process, leaving Cersei powerless), but he's already her Hand. Jaime Lannister might be a suitable candidate, but it's unlikely he'd be willing to help the Targaryens seize power back from his own house.
If Dany wanted allies in the North, Bran Stark qualifies on paper, but his role in the show has always been completely distinct from the political machinations that define King's Landing and Dany's return to Westeros.
For now, the identity of Daenery's future husband remains a mystery — and for the first time in a while, Game of Thrones is way ahead of us.