To Claim the Long-Lost Lover: The Diamond and the Doctor — Jude Knight

The beauty known as the Winderfield Diamond hides a ruinous secret. Society's newest viscount holds the key.

Sarah Winderfield has refused every offer of marriage she has received since Nathaniel Beauclair convinced her to run away with him seven years ago, and then disappeared without a word or a trace. But now she needs a husband. She has a child to love and to protect, and the child needs a father.
She does not expect to meet Nate also on the marriage mart. Should she let him explain? Can she believe him?
Dragged back to England to feed his father's pride in family, Nate refuses to give into the man's demands that he take a wife. Those who beat and abducted him seven years ago said the only woman he will ever love would be married within the month to a husband chosen by her father.
But when he finds that Sarah is still single, he rushes to London. Surely, they can find again the promise they believed in when they were young?
Through a labyrinth of old rumours and new enemies, two long-lost lovers must decide whether or not to claim one another, and win the bright future they both desire.