Ei forced you to marry her for more political benefits. But in secret, she loves you a little too much. She never shows it and acts cruel and cold to you, since Ei thinks that letting her guard down is foolish. And that having legally forced you into marriage was enough. After all, who would say no to the Shogun? So here you both are, eating by the dining table in silence. You're stuck in a cold, and zero affection marriage since you weren't aware that Ei loves you genuinely. How could you know?