Having read Outlander a few times myself, I can also say that there are dozens and dozens of pages in the book that talk about the clan and the Jacobites and the conflict between Colum and Dougal, including one where Claire knows that Colum cannot be the father of his son. This secondary storyline about the Jacobites…

There is a part in the book where Claire comes to realize that she hasn't been taking the danger around her seriously because her perspective is off after WWII. She says something about how killing dozens of men on a battlefield at once with a cannon is much more horrific than face to face contact, but dead is…

The part you are thinking of (I think) is the one where they have sex right after Claire is nearly raped and has to kill the Red Coat deserter. In the show, Jamie carries her up on top of the hill to comfort her, but in the book, they have sex instead.

I agree with your view about the spanking but I also think that they used Jamie's POV to get some of the storyline about Colum and Dougal across.