Page, Sharon. Wicked dukes.

"Ten years ago the Duke of Sinclair called off his wedding to Portia after revealing his debauched past and dark carnal desires. Portia has never known love since. Now she is in Sin's presence again, on a secluded island, witness to an orgy of sexual delights that thrill her in ways she never dreamed possible. Sin has never forgotten Portia's beauty or innocence and he is shocked to find her tied to his bed when he arrives on Serenity Island. But he soon finds his long ago love curious, then aroused, by the carnal acts all around her. Sin has secrets he can never reveal, but in Portia he discovers a sensuality that knows no bounds."--Page [4] of cover