The actual sex and nudity has fallen off since the first few episodes in season one. The problem with the show is it uses violence, sex (including homosexual), and nudity as shock value rather than adding anything to the plot. I am not opposed to it as long as it make sense to the development of the story.
I'm reading the first book now, and though the show sticks pretty closely to the book, I have been surprised by how relatively little of this stuff is in the book. Shock value, for sure.