Was Klaus sexually abused and that is why he didn't want to be touched?

It was never outright said, but he also mentioned that it has to do with the teacher and that it’s supposed to be a secret. He also was late to come home all week so I really think that this was the case.

Based on the other comments, it is most likely true. The arms of the teacher coming towards Klaus means that he was obviously touched in an uncomfortable way. He doesn’t want to be touched which is unusual so he probably was sexually assaulted. He probably didn’t eat, play, or bathe because he could not stop thinking about the situation.

Yes!