Falling action is the series of events in a story between the climax and the resolution.  In Eclipse, the falling action is the events after the big fight for control between the werewolves and vampires.

In the falling action, the initial conflict has been resolved with the events of the climax.  Victoria is no longer a threat.  However there can still be lingering problems resulting from either the initial conflict or the events of the climax.

In this case, the falling action is affected by events before the climax, namely Bella and Edward’s pending marriage.  Another problem resulting from the climax is Jake.  Jake is still in love with Bella, and that is a conflict that is unresolved until he leaves.