I disagree, but only because I think I figured out the ending, how GRRM told the show writers, and I can see how they interpreted it.

Possible spoilers: I think Jon is supposed to kill Daenerys and the writers couldn’t figure out why so they just made up dumb shit. But the reason he kills her is to forge a sword (Lightbringer) to destroy the white walkers. And Daenerys agrees to it.

"To fight the darkness, Azor Ahai needed to forge a hero’s sword. He labored for thirty days and thirty nights until it was done. However, when he went to temper it in water, the sword broke. He was not one to give up easily, so he started over.

The second time he took fifty days and fifty nights to make the sword, even better than the first. To temper it this time, he captured a lion and drove the sword into its heart, but once more the steel shattered.

The third time, with a heavy heart, for he knew beforehand what he must do to finish the blade, he worked for a hundred days and nights until it was finished. This time, he called for his wife, Nissa Nissa, and asked her to bare her breast. He drove his sword into her living heart, her soul combining with the steel of the sword, creating the weapon known as Lightbringer." -Tyrion tells this story in book 2 I believe

“According to prophecy, our champion will be reborn to wake dragons from stone and reforge the great sword Lightbringer that defeated the darkness those thousands of years ago. If the old tales are true, a terrible weapon forged with a loving wife’s heart. Part of me thinks man was well rid of it, but great power requires great sacrifice. That much at least the Lord of Light is clear on.” -Book 2