Marrying a Tully isn't the same as marrying the King in the North. That's like marrying Loras Tyrell in stead of Jamie Lannister, Stannis Baratheon in stead of Rhegar Targaryan. It's a huge disrespect. It's was a chance to merge his ****** family with THE family in the north. One day his grandchild would have been King in the North and his bloodline would be considered royalty. Now, he gets the retard, coward Tully. No way it makes it up to him