When the MC's father find out about the cheating and pending breakup he gets the idiot fiance's father to agree to a fidelity clause to their engagement, when the engagement is officially canceled but after he is engaged to insane girl (he even tried to frame her of cheating on him with the prince) proof of his cheating bought forth and his family looses everything (including territory) then and there due to the penalty, recovering costs wasted and compensating for the insults and offenses (yes plural) against the MC, etc.