On page 806, Nick describes the way that Matty's kids felt at their Grandmother's funeral when they saw their dad for the first time as a brother and as a child. This same logic seems to apply to other characters. There's Nick the guy who has two kids and a wife and a job, but hidden beneath that there is Nick the murderer who his wife doesn't know. I think it's really interesting to think about the way that Nick may be a father and a husband to the world, but he will always be the murderer in his heart.