Raja, excellent analytical mini-dissertation.
Richard and Emily do need each other, but while they are on break, Richard can go woo Paris with his barbershop quartet, and Emily needs to rebel a bit. There's a WildEmily (as witnessed by DrunkEmily) that's screaming to get out, and someone needs to feed the fire. A Jess type could do that, except I don't want to picture that.
Maybe Digger can bounce from daughter to mother... at least temporarily.