Almost only counts in horseshoes, hand grenades and tactical nuclear weapons. ;)
How many sex scenes were there between Cersei and Jaime? Why do we need to see them? Jaime is portrayed as a good guy in the story (except for the first season), which sort of normalizes his behavior in terms of his popularity to the audience.
As I recall, four scenes in eight seasons. I guess the same question could be asked about any of the sex scenes in the show. Personally, I think all of these detracted from the story.
WRT Jaime, I believe he's being portrayed as a flawed, but basically decent man. As to whether his incestuous relationship is being portrayed on the show in such a way so that the audience will accept it as normal, we will have to disagree.