Responses
you got it right, she had received a necklace from an anonymous sender and johan misunderstood that as her having an affair/planning to leave him (i think his anger was also related to him seeing her as "the same" as the previous empress, who had left him and married the emperor) so he became violent and locked her in a room.
i mean, how surprised are we that a dude that married a 14yo just because she looked like his first love was abusive in some moments, really?
Wait I'm confused. Idk if its deliberately ambiguous or if I'm just slow asf but what exactly happened between shuri and her husband and why did she run away back to her mother. What is understood was that her husband hit her because he thought she was having an affair???