sharing a bed with ur kid and talking abt things is totally normal but i do agree on the other aspects you have brought up honestly reading this the entire story is very twisted. it appears both the mother and the daughter have their own sadistic personalities and somehow the mother thinks that her daughter is kind of like an reflection of her
The closeness is normal but usually there's a time when kids coming of age want more distance from their parents naturally. But maybe bcs mom and Rosa were healthy with boundaries before she doesn't need it.
Mom is definitely crossing boundaries NOW tho fucking her boytoy where Rosa can hear it and pushing her into a forced new family dynamic etc.
If I was Rosa I'd move out and cut the contact to a certain degree. She's really not angry enough at her mom who ultimately is at fault here.
I don't think this mother daughter relationship is going to stay healthy....
I think the dynamic is off too. I stopped going in my parent's bed when I was at most 10? I have a big sense of personal space though, so it could be that. I think everyone's dynamic would be different.
But yeah, the fact that she brought up that they like the same things, and forcing the two together is putting me off. It feels like the mom is trying to get them to have an affair or something. Which is so messed up, especially since she keeps calling him her step dad.

Maybe I am reading too much into things, but the chapter when the mom and Yeonwu were fucking and the mom stares at the photo of herself and her daughter? Gross. The mother is implied to know her daughter extremely well (being that they "like all the same things") And she insists on forcing her daughter and Yeonwu to spend time together; when she comes home she always asks specifically about what Yeonwu and Rosa did TOGETHER. The only ever talk about Rosa. They don't have any other topic to talk about? I have an inkling dear Mother anticipates her daughter's interest in Yeonwu (maybe even knowing their implied history together). The mother's obsession is with her own daughter, and no real feelings for Yeonwu at all?? But I am also NOT close with my mother, so maybe this weird closeness (frequency sharing a bed?) between them is . . . uhm, normal?