More than a mistress - Mary Balogh

When Jane Ingleby interrupts a duel in London's Hyde Park, Jocelyn Dudley, Duke of Tresham, gets shot, and Jane, late for work at a milliner's workshop, loses her job. She is angry enough to demand a new job of Jocelyn, and he is angry enough to hire her - as his nurse. Her blue eyes are the sort a man could drown in - if it wasn't for her imprudence. She questions his every move, breaches his secrets and touches his soul and soon the dangerous duke is offering her a different job - as his mistress.

Jane tries to keep it strictly business, an arrangement she is forced to accept in order to conceal a treacherous secret. Surely there is nothing more perilous than being the lover of such a man. Yet as she sees through his devilish facade and glimpses the noble heart within, she knows the greatest jeopardy of all is the rising passion that could tempt her to risk everything. . .