SPOILERS - The Better Sister - Alafair Burke

In the novel, more than mid-way through the story, it is revealed that Adam had been an abusive husband.

Adam had mistreated Chloe. He had also abused Nicky before they split up all those years ago. Chloe had kept it a secret.

Nicky and Ethan had privately been communicating. Ethan had informed Nicky about the vicious fights he heard between Adam and Chloe.

Nicky drove from Ohio to Long Island and killed Adam.