Responses
Not really it’s king of an egg and chicken probablem, adult sou remembered what adult rin did to him when he was younger, and therefor cheated, got him mad and drove him to do that to younger rin. It’s the same for adult rib who did that because he remembered what adult sou did to him when he was younger. They just both cheated on the other as a young and older version and got mad at the other about that
the first to blame for all of this is the adult SOU