What Zoey Saw — Katherine Applegate

In the sixth book in this popular series, Zoey makes a shocking discovery. What Zoey saw is turning her life upside down. She used to think her family was perfect, that their parents were really in love. But what she saw changed all that. And it's making Zoey think about love in a whole different way.
Zoey sees her life turning upside down when she makes a shocking discovery. She used to think her parents were perfect and totally in love. But what she's seen changes all that--and it's making Zoey think of love in a completely different way.