@justforthelulz Uh... would you believe me if I said I somehow forgot there were four couples?
Although, if you think about it, this reincarnation stuff is pretty different for them compared to the other three.
They didn't really have an unfulfilled romance in the past or anything. Their love story is relatively new and only came about because Hikari didn't quite regain all of his memories.
Whatever that implies, I don't know.