Wanton by Carole Mortimer

Until a year ago Xavier Asherton, the Duke of Northcliffe had known only three things about Lady Diana Fitzwilliam.

She was young, beautiful, and a widow.
Since then Xavier has also learned, after his younger brother, Raphael, died in Lady Diana’s bed, that she was his brother’s mistress.

Unfortunately, for many past tormenting and sexually frustrating months, Xavier has also learned that Lady Diana is now the only woman he wishes to take to his own bed.
Being propositioned by Society’s most eligible bachelor, Xavier Asherton, the Duke of Northcliffe, would no doubt be a thrill for any woman. Unless they are Lady Diana Fitzwilliam. Because Diana knows, no matter how much the duke might express his desire for her, that he must also harbour anger toward her for the manner in which his brother died.

Nevertheless, the passion and desire burns so hotly between the two of them they are unable to deny it. Or each other.
But Diana fears what will happen when or if Xavier discovers her secret.