Justin Cronin said this quote

It was more than physical attraction; it was the broken thing inside him she loved most of all, the unreachable place where he kept his sadness. Because that was the thing about Peter Jaxon that nobody knew but her, because she loved him like she did: how terribly sad he was. And not just in the day-to-day, the ordinary sadness everyone carried for the things and people they had lost; his was something more. If she could find this sadness, Sara believed, and take it from him, then he would love her in return.