The Secrets We Keep by MJ Masucci

I had it all – the riches, popularity, and good looks that made me stand out. But deep down, I was wounded. My mom had left, and my dad, well, he was on wife number four. With this latest addition to our family came a stepsister, Taryn.
I found amusement in tormenting her. She was an easy target – a gorgeous, tortured target. Maybe it was a way to distract myself from the agony which consumed me.
Then I discovered her journal – it was a treasure trove of her deepest, darkest secrets.
As I pushed her to confront her own demons, something unexpected happened. In the process of releasing her pain from those pages, I felt a weight lift off my shoulders.
It was like the act of forcing her to confront her fears somehow allowed me to confront my own. And as we grew closer, I knew it would implode with one secret I couldn’t reveal. The one which would cause devastation and send her back into that dark place… and me as well.