Dark Places — Thomas Altman

She though she married the perfect man-but now she must survive his terrible secret. Christy McNair's newlywed life has been idyllic-until no. Suddenly, three strangers are shattering her world. One is a handsome loner, obsessively pursuing her with arrogant lust. One is a mysterious woman, with a frightening claim on her most intimate world. And one is her husband, the man she though she knew, whose dark secrets will plunge Christy into the greatest nightmare any would could face-when she is forced to fight for her marriage, her sanity, her very life.