Captain Ingram's Inheritance (Rothschild Trilogy #3)

Frank Ingram, an impecunious officer, is seriously wounded at Waterloo. Rescued by Lord Roworth, he meets Roworth’s sister, Lady Constantia, an angel of mercy. But Frank and Connie are each hiding a terrible secret they are sure will prevent marriage to anyone, let alone each other. Also published under the title "The Captain’s Inheritance."