Yours Until Dawn by Heather Boyd

Drew Finch, Lord Sullivan, has spent two years searching for a bride…though in truth, his quest has not been in earnest. Having lost his first wife and son in childbirth, he’s a shell of a man, in no hurry to see his beloved replaced by another. With increasing pressure from his father to do his duty to the family, Drew seeks out the help of an acquaintance, Miss Hillcrest, to aid him in making a match. He’s long been her admirer…but he never planned to fall for the matchmaker herself.
For reasons known to very few, Aurora Hillcrest feels like a fraud, passing herself off as a lady amongst the ton. With her dear cousins now married, and no plans to wed herself, she feels adrift and in need of a purpose. Then Lord Sullivan asks for her aid. She’s keenly aware no lady wishes to compete with a ghost, and Drew hasn’t so much as kissed a woman in years. To that end, she suggests he ease himself back into intimacy by taking a lover…but she never planned to find herself conscripted for the task.
Passion blazes between them in secret, and before long, Drew is proposing…many times over. But Aurora’s refusal is adamant, for reasons she won’t share. Reason that, should he ever learn of them, might harden Drew’s heart to Aurora forever.