hehe...you are back..
it seems you already know very much about the story, or how the novel is going from here..
the part 1 is about Bing's current status of living, his condition, dilemma about into or out of marriage, and about Sydney as a place..Serena is kind of a swift passer-by in his life...
his major stories are in his past..
and Shadow, as I said before, is referring all lives under the 'sky', not necessarily married or divorced, happy or unhappy..because really.. where there is sun, there is shadow..