His to Keep (Regency Scoundrels #2)
Marly Mathews

Independent and free spirited, Gemma St. Martin wanted to dictate her fate in life. When she sets her sights on a totally unsuitable husband, however, Mallory St. Martin intervenes, and hires her a keeper—the mysterious Scotsman, Archie Campbell.
Archie loses his heart to Lady Gemma the first time he sets eyes on her and decides to make her his, but a tragic secret connects both families that just might destroy their chances of finding happiness.