"In a coat of gold or a coat of red, a lion still has claws."
It's hard talking to people who haven't read all of the installments to the "Song of Ice & Fire" series about Robb Stark. If there's one thing that Jimmy Darmody or a Lannister could tell you: It's that it's of utmost vital importance to pay your debts.
Duty should take presidence over emotions, especially when others are depending on you, and his father understood that notion. That's why he married Catelyn without loving her in the beginning: He had a job to do for the good of the Seven Realms and he did it.