Why does McEwan return back to the The trials of Arrabella

The introduction to relationships and love in the book is also sour. We have Emily and Jack Tallis who never see each other, and Hermione and Cecil Quincey, who are going through a divorce, sending their children to be looked after by the Talis's. This an opportunity for McEwan to set the tale of bitter love in others, and then juxtaposing Cecilia and Robbie's love as being sublime and sweet.The play Briony writes, "The Trials of Arabella" are a metaphor for what is about to come of Briony. The "spontaneous" (remember, all of Part One happens in a day) child is "inexperienced" and about to commit a crime that will see the world "rise up and tread on her."