Roarke's Kingdom by Sandra Marton

Almost three years ago, Jennifer Winters made the toughest decision of her life. She gave up her baby for adoption. Now Jennifer just wants to see her baby and make sure she's happy and well. She must be. After all, she was adopted by a secure, middle-aged couple. But the middle-aged couple doesn't exist. In their place is Roarke Campbell. Is it he who adopted Jennifer's daughter? The only certainties are that Roarke is a ruggedly gorgeous, emotionally unapproachable billionaire--and that once Jennifer goes into his arms and his bed, she's on a one-way ride to disaster.