He is too stupid and arrogant to feel despair. What he does next is brazenly go to a party in the palace, where he was invited basically because all nobles were, demands money from Etheria because "you've got land thanks to this, so share the profit" or something like that, and disrespects the new crown prince to his face, which gets him exiled from the capital on the spot. Then he raises taxes in his new land beyond limits allowed by law, and gets put under house arrest with an administrator installed by the government to manage the land. He's trying to divorce the 'heroine' hoping to get a better political marriage, even though he will lose the land and title because they are actually hers (the king instructed the church to deny all of his requests, but approve if she ever sends one in). Later he started (ineffectively) plotting stuff with his newborn child, so the king had to have the baby assassinated just in case to prevent all risk of insurrection.
Because of him his mother was divorced and had to return to her original family with his sisters.
The heroine's mothers original family actually renounced their baron title (that's where it came from) in order to completely cut ties, and became full-time merchants, since that's where most of their income was coming from already, while the land was at best break-even. He actually tried to ask money from them too, but they basically said who are you, and kicked him out.
MC got a non-inheritable title and land as compensation so she can be independent without having to marry anyone. She decides to create her own school focused on engineering and invention there. The queen actually immediately figures out she was behind all of this because of some deliberately obvious clues MC left, but the fact that the prince couldn't only further proved his incompetence, so she just makes MC promise to advise and support the new crown princess.
