He also said what happened in the past was his fault. If it refers ot the Empress' death then he's been lying all along and enjoying the Emperor's favour.
Song Yiting telling her sister that she hasn't loved anyone or lived this life is a good reminder. So is LSL pointing out that FL is more cruel and ruthless than NH by framing him for rebellion. Of course, can't blame FL as she wants to survive but she is still thinking of this as a novel/game.