Charity Nightingale Heals Her Husband by Aydra Richards

Charity Nightingale, once a courtesan of some renown, has retired from her career with enough funds to see her through the rest of her days. What she wants more than anything else is a peaceful, comfortable life. What she gets is a chance meeting with the husband she believed had died years and years ago.
Captain Anthony Sharp has returned to England at last, after a family tragedy has unexpectedly made him a duke. The last person he expects to encounter upon his return is the woman he took to wife some sixteen years ago, whom he thought had long predeceased him.
Charity doesn’t want to be a duchess. Anthony needs a wife and an heir. But Charity has got a soft spot for the lonely, battle-scarred man who has replaced the young soldier she knew so briefly a lifetime ago. In return for his assistance in seeking the annulment which will put an end to their inconvenient marriage, Charity agrees to teach her husband the skills he will need to find a love match on the marriage mart—but can she avoid becoming seduced by a lover of her own making?