It's hell when imaginary boyfriends kick you to the curb and then you have to pretend you're so hot they want you back.
Given Amber's propensity for fantasy, this is probably what
really happened:
Poor old Dave was at the library, or near the library (where he could be seen), by sheer chance, and Amber spotted him.
He
may have spotted her, too, and then turned around and walked away.
On that scrap, that fragment, of a real-life event, Amber then constructed her tale.
I'm a pro at this; I would know.