"How's this ideal?" Yuya's expression sinks a little. "I think I can say better than most people that being in separate pieces isn't a perfect solution."

And he considers his situation to actually be a problem that needed a solution. Why would Rita benefit from having some sort of weird separation in herself. "It comes with a lot of problems too, like getting blamed for stuff the other person with your face does."

And having the evil violent piece pushing all of you to merge into a single powerful monster to destroy the world... but that's probably just a him problem. "Maybe... maybe you got separated based on the parts you'd want to keep? But you're still missing stuff that makes you Rita. Both of you."