Season of the Rake by Jane Charles

Angelo Evans, the Earl of Bolton made a promise to his mother—that he’d marry before Christmas. As this would be the last Season he would ever enjoy, Angelo is determined to embrace all of life’s pleasures: brandy, women, and gambling. Come the autumn, he will find a miss, marry, become respectable, and settle into a boring existence.
Lady Octavia Kepple is finally free. Now out of mourning, she intends to embrace the Season as only a respectable widow can: find a lover. She doesn’t want just any lover, but the gentleman rumored to be the best lover in England, the Earl of Bolton. Now, she just needs to convince him to be her rake for the Season.
Though intrigued by Lady Kepple’s proposition, and his desire for her cannot be denied, Angelo doesn’t want to be tied to one lover during his last Season of freedom. However, Lady Kepple is most persistent, and an agreement finally reached might be more than either of them bargained for.