Jon marrying Danerys would have made him complicit in everything she's done - including roasting Samwell's family alive. It's not the incest that ooks him out, it's that she's a psychopath. She's a convenient psychopath when they need her armies but once her armies are a liability he's done with it. She would have had him murdered eventually anyway - she's rejected everyone she's ever loved because they get in the way of her power and double-crossed her way out of every threat. The balance with Jamie and Cersei is perfect: Jamie surrenders to love over duty while Jon chooses duty over love. That's why he was never going to end up with Brienne - he's not banging his sister because he can't find another girl, he's banging his sister because what matters to him more than anything else in the world is banging his sister. The only people who ever gave a shit about the White Walkers were the Northmen. The only people who had any sense of the White Walkers were the Northmen. For everyone else, The Wall was like Australia - a convenient place to shunt people so you don't have to execute them. Therefore, the only time anyone really rallied behind the North was when it could be demonstrated beyond a reasonable doubt that they would bring about the end of Westeros. Really, Bran is order and the Night King is entropy; Bran had to employ strategy across the timeline in order to defeat the Night King, who basically marched guilelessly across the landscape. The Battle of Agincourt took a day. The English were outnumbered somewhere between 2 and 6 to 1. They took a couple hundred casualties max and slaughtered something like ten thousand Frenchmen.
Well, Danerys had the ultimate weapons, the most fearsome army in the world, and the love and respect of powerful people around her. She was going to be queen. Jon had a chance to marry her, take a woman he was truly in love with, and together they could have been a great duo. Jon could have reined her in, tempered her anger and arrogance. She wanted desperately the love of the people and saw that the people loved Jon in a way they didn't love her. This is a great bargaining chip in the relationship -- she could follow his example and learn from him and become the kind of leader she so wanted to be. She lost another dragon and then her best friend, and losing Jon as a lover was the thing that pushed her over the top. Imagine if instead Jon said "fuck it I don't care if she's a little more closely related for comfort, I'm going to marry her anyways", it would changed everything. As a duo, fire and ice, they would have a really good shot I think at balancing the whole shebang and becoming something great and worthy of the love of the people. What do you mean by Bran employing strategy across the timeline?
The "woman he was truly in love with" rejected his ways, ratted him out and took part on a murderous raid on his homeland. He tried that alliance thing several seasons ago and and ended up with him ultimately murdered by his own squire. Ygritte was a far gentler human with a whole lot less to lose than Daenerys and he ended up holding her as she bled out, too. She saw that people in WESTEROS loved Jon in a way they didn't love her. She saw what happened in that game in Mireen - she ended up betrayed by her paramour and had to wipe out his entire social class. There's no bargaining here - both parties to your prospective relationship have tried it before and had it end in betrayal, catastrophe and battles that killed thousands. Sure. But over the top she went. The whole of her arc is "how did this person become so mean." She's earned it, no doubt. Ultimately, though, nice people don't march under the banner of the Symbionese Liberation Army. The last three episodes of the series are everyone who knows imagining what would happen if Jon did this. This argument right here is why Tyrion betrayed Varys. It's why Sansa gave up Jon's secret. It's why Tyrion betrayed his queen and freed his brother - half the important players in the game think Daenerys can be reined in, the other half think she's a Targaryen. And even with peace ringing out, even with her enemies defeated, even with everything to gain and nothing to lose, she goes Targaryen in the end. It is not my fault, said the scorpion. It is in my nature. Jon could have reined her in, tempered her anger and arrogance. She wanted desperately the love of the people and saw that the people loved Jon in a way they didn't love her. This is a great bargaining chip in the relationship -- she could follow his example and learn from him and become the kind of leader she so wanted to be.
She wanted desperately the love of the people and saw that the people loved Jon in a way they didn't love her.
She lost another dragon and then her best friend, and losing Jon as a lover was the thing that pushed her over the top.
Imagine if instead Jon said "fuck it I don't care if she's a little more closely related for comfort, I'm going to marry her anyways", it would changed everything.