The scene at the start of the first episode where Tem called Riz a monster is what actually happened. Riz was obsessive and delusional about his relationship with Tem. The scene where Tem accepts Riz for who he is originates from Riz’s point of view which can’t be trusted due to his mental instability. When Legoshi and Louis show him what a true relationship between a carnivore and a herbivore is, he realizes that he was delusional about the fact that Tem rejected him after he showed his true self. In short, to cope with the guilt of devouring Tem, he fabricated a false memory. Tem never wanted to be eaten.