Claire could never be a prop. Therefore when Jamie beats her, the character development does not occur because he hits ‘a woman’ but that he believes it is both right and HIS right to curb his wife’s behaviour that way. And then Claire shows him that it isn’t. That’s a much richer and interesting storyline than what we are used to hearing, and it is something that lasts throughout the books — from the nettle scene (which I personally dislike but can perhaps understand) to the occasions where he wants to shake her and she wants to slap him.
The physicality of the characters is always intense, whether in passion or fury, and part of what makes them so compelling is how they bring each other back from the brink of violence.
Love your comments here! I think time and time again in these books, both Claire and Jamie are very physical beings. Not just sexually, but they use their bodies and movement and physical space to process information and learning and evolving. The “spanking” scene is among the first examples of this, which is part of what adds to the “shock value” to people who only see what’s happening on the surface. When I re-read it after knowing these characters through all the books, I see it through a different lens.
Also, media has trained most of the audiences today to not bother looking past what’s happening on the surface. Very little is done that truly explores deeper connections, as Outlander is challenging viewers (and readers) to do.