Becoming Lady Dalton by Carrie Lomax

She has everything a woman could want. The last thing she needs is a man.
Mrs. Viola Cartwright’s fortunes took a turn for the better the day her sister wed the Earl of Briarcliff. As a lady of leisure, her only responsibility is to her son, Matthew – and he’s headed off to school in a few weeks. Leaving her with ample time to pursue her interest in music, acquiring a long-denied education, and dancing – lots and lots of dancing. Until a series of jewel thefts casts a shadow over the final weeks of the London season….
He’ll take on Bow Street to save her.
Lord Piers Ranleigh, sixth viscount Dalton, has desired the mysterious, lighthearted widow ever since she arrived in London. But Viola parries his attempts to court her by pushing him into the arms of another woman. Piers plays along–for a while. When suspicion falls over Viola he must decide how much he’ll sacrifice to protect her.
A past she can’t escape threatens a future they both desire.
When a figure from her past threatens Viola’s new life, she must decide how far to trust Piers – and learns just how deep a family’s love runs.