Sean pretty much accepting Ned's family as his own, doing everything in his hand to save them from their horrible destinies.
Catelyn asks Sean to marry her "again", saying she wants to renew their vows. Or, more likely, because she has figured out that Sean is not the Ned Stark she married.
Sean tells Arya that he understands why she hates Sansa so much, and does his best to make peace between the sisters.
Heartwarming for Stannis, that he tries so many times to get Renly to give up his claim, as he does not want to have him killed.
