In season eight, Jamie leaves Brienne in Winterfell to return to King’s Landing and his certain death. It was assumed his enduring love for Cersei compelled him to return. However, "Jaime doesn’t just make up that list of terrible things he’s done in Cersei’s name. His addiction to her really has driven him to perform horrific deeds. And because of that, he believes he is just as bad as his sister. He doesn’t think he deserves a better life with Brienne. He only deserves Cersei," the article states.
As he rides away, Ser Brienne is broken but feels Jamie will die still believing he is a monster.
This theory is validated in light of Brienne's actions in episode six, where she is seen completing Jaime’s entry in the White Book, with all his honourable moments. "She ensures the world will remember Jaime not just as the Kingslayer, but as the good man she knew," the theory concludes.
This article originally appeared on marie claire.