At Last Comes Love by Mary Balogh

Only desperation could bring Duncan Pennethorne, the infamous Earl of Sheringford, back home after the spectacular scandal that had shocked even the jaded ton. Forced to wed in fifteen days or be cut off without a penny, Duncan chooses the one woman in London in frantic need of a husband. A lie to an old flame forces Margaret Huxtable to accept the irresistible stranger’s offer. But once she discovers who he really is, it’s too late—she’s already betrothed to the wickedly sensual rakehell. Quickly she issues an ultimatum: If Duncan wants her, he must woo her. And as passion slowly ignites, two people marrying for all the wrong reasons are discovering the joys of seduction—and awaiting the exquisite pleasure of what comes after….