Kaleidoscope Hearts (Hearts Series, 1)

He was my older brother's best friend. He was never supposed to be mine. I thought we would get it out of our system and move on. One of us did. One of us left. Now he’s back, looking at me like he wants to devour me. And all those feelings I’d turned into anger are brewing into something else, something that terrifies me. He broke my heart last time. This time he'll obliterate it.