Jaime burned Cersei's letter in AFFC and refused to help her. But don't you think he HAS to come for her? That he owes her?
Sorry it took me so long. Yes. In a way.
I mean, lover or not, cheater or not, Cersei is still his sister and the mother of his children. She’s still family, and a good brother would not ignore his sister’s cry for help. Especially since a big chunk of the crimes she’s accused of – adultery, incest, high treason – Jaime is equally responsible of them. He’s the one she committed adultery with for almost twenty years, the father of her illegitimate children after all. If you think about this, it’s undeniable that he has some moral obligation to get cersei out of this ordeal. It doesn’t feel right that Cersei goes down without him. This is one way to look at it.
The other is that, by burning the letter, Jaime sets boundaries for the first time in a relationship whose lack of boundaries had devastating repercussions not only on the twins themselves, but on the whole realm. I cannot blame him for choosing not to prioritize Cersei over himself for once, for refusing to risk his life for her (let’s be real: Jaime championing for Cersei without his sword hand would be tantamount to suicide), for wanting to break this cycle of codependency that induced him, among other things, to trade Casterly Rock and a future lordship for an existence completely devoted to her, as her guard and secret lover. In a way, Jaime already gave up his life for Cersei. Mind you, it’s not like he did it for genuine altruism (they both are greedy and selfish in this relationship, they both take more than they give) no, he did it because he wanted his burning desire of her fulfilled 24/7. But this hunger consumed every other possible future Jaime could have, and now he’s middle aged, handless and full of regrets.