I read this fragment from the novel and, to be honest, in original this scene still contains some disturbing rape undertones. It still Jaime forcing himself on Cersei while she's resisting. The fact she embrace it after a while doesn't help, because it seems to fall into "It's not rape, if they enjoy it rationalization" trope.
You should also consider the fact that in the show you don't have descriptions to tell you what character feels or think about. The problem seems to be not the fact that they did not follow the original enough, but the fact that they were to faithful, falling into trap that many adaptations face. They probably intended for Cersei protests to mean the same thing as in the books, which means she simply didn't want to have sex next to Joffrey's corpse and that's why Jaime said: "I don't care". Without proper descriptions an already bad scene looks even worse in the show.
