The Spinster's Secret by Emily Larkin

Penniless spinster, Matilda Chapple, lives at isolated Creed Hall, dependent on the austere charity of unloving relatives and under pressure to marry a man twice her age. In an attempt to earn enough money to escape this miserable existence, she writes a series of titillating 'confessions'. Her secret is safe — until battle-scarred Waterloo veteran, Edward Kane, reluctantly accepts the commission to uncover the anonymous author's identity. While staying at bleak Creed Hall, Edward finds himself unaccountably drawn to his host's lonely niece. Can Matilda conceal the secret of her scandalous writings, or will Edward discover that the spinster and the risqué authoress are one and the same person? And when Matilda feels the need to experience sex as her fictional courtesan does—will she lose her heart to Edward, along with her virginity?