Sumire, just accept his love.
I never guessed the reason why he didn't divorced of Karin was because he was thinking his marriage as a plan B if the things don't go well with Sumire what is problaby the same reason why he didn't ended his marriage with Sumire when he was cheating her. I know his main "quality" is his weakness, but this is insane, Karin flirted with anotherman behind his back, lied about money and and he still thinking her as possibility !?
My guess is he connected the "dotes" left by Sumire and was fooled to belive Karin was the blackmailer. Now he is cutting karin's allowance or something like that.