Jordan, Sophie. Rogue files

"To save her impoverished family, Marian Langley will become a mistress. But she will not be just any mistress. Marian intends to become so skilled, so coveted, that she can set her own terms, retaining control over her body and her fate. Only one problem remains: finding a tutor... Other men deprive themselves of pleasure for propriety's sake. Nathaniel, Duke of Warrington, would much rather be depraved. He slakes his desires with professionals who ask nothing of him but his coin. Marian's proposal--that he train her without taking her virtue--is an intriguing diversion, until their lessons in seduction spin out of control. When Marian is blackmailed into engagement by a man she despises, Nate impulsively steals her away. Though he never intended to take a wife, he can't tolerate the idea of Marian forfeiting her freedom to another. But can he bear to give her what she demands--a real marriage?" --