The man looked over at the woman. “The things I do for love,” he said with loathing [italics mine].
I’m used to thinking of Jaime as having a turning point re: his relationship with Cersei when he learns how many other men she’s been sleeping with. However, here we see him already addressing her with “loathing.” His dialogue before Bran’s appearance can be summed up as “will you shut up and have sex already!”; his predominant emotions are boredom and impatience.
No doubt Jaime still believes he “loves” Cersei at this point, but if this was ever a relationship of mutual emotional gratification, it already isn’t anymore.
Still … that’s one great line there.