Devil's Promise — Samantha Cruise

Driven by insatiable desires, Megan Spawn leads a secret life filled with taboo liaisons. Luckily, she doesn't have to choose when it comes to a lover--she's married to two men, the notorious outlaw Devin Spawn and the distinguished Caleb Walker, who only whet her appetite for sensual pleasure. When Megan catches the eye of Caleb's gorgeous partner, Dr. Randolph Sinclair, temperatures begin to rise. No woman can resist the passionate bedside manner of Doctor Sin. Not even Cassandra Huntington, a red-headed beauty who would rather solve the problems of the world than risk accepting his stimulating cure, is immune to the seductive charms of a sinful rogue in a white coat.
Note: excessive physical violence inflicted on heroine by villain