"Why is he surprised Claire is upset?" (tongue in cheek) Because boys are dumb, lol.

By my lights, what happened is that he had been pressured multiple times to get with one of whores at the whore house he visited with the Bonnie Prince "Mark Me." In one particular situation, things went a bit far - and he got aroused without thinking of his abuser. In his excitement of feeling without thinking about Black Jack, he ran home to his wife to be like: "Look! PROGRESS! Let's do all the things!" But the situation was all confusing, and the location/people involved instantly made lots of tension....

Because at the same time, Claire was trying not to push. She was trying to be understanding. She was trying to change history... in a time where ladies were left at home and waxed their honeypots at their friend's house. She felt totally neglected by Jaime, totally invalidated by society/history, and fucking pregnant - which makes anyone irritable to begin with. But she wasn't being totally honest with Jaime about all this... because of his trauma.

Bad communication all around. Also... accurate when it comes to how some people deal with recovery from trauma. Not the whore house bit... I don't think - but rather the not pressuring, and the not communicating, and the breakthroughs that may seem out of the blue bits.