Shadow of the Swan (Hidden Empire) by Nicole M Cameron

Few know that beneath the British Empire lies a world of supernatural creatures, dangerous magic, and passionate romance. Enter if you dare… In the golden years of the Victorian era, historian Louisa Wallingford is shocked to learn that an ancestor’s pact has promised her hand in marriage to a sadistic Fae king. Her only chance of escape from an eternity of torment is another marriage—to a vampire. Louisa’s impromptu wedding sweeps her into a hidden world of dangerous magic users and seductive supernatural beings. And her new husband, vampire knight Henry Carstairs, is one of the most deadly creatures in this new domain. But what begins as a marriage of convenience unexpectedly turns into a passionate love affair between the innocent historian and the sensual vampire—until a conflict between the British Empire and the Land of Faerie threatens to tear them apart. Now Louisa and Henry must find a way to outwit their enemies in both realms … or be separated forever.