Behind the Duke's Door — Lynne Silver

On her wedding day, Lady Elizabeth Fentworthy knows that while Harry Reedburn, Duke of Walthingburn, is marrying her, his kisses are reserved for his lover, Arthur. Their convenient marriage will save Elizabeth from becoming an old maid and give Harry an heir -- though their wedding night does not go as planned....

Harry needs Arthur to become aroused -- and Elizabeth feels an unexpected desire seeing the two men together. Is adding Arthur to their marriage bed the key to unleashing the passion they need?