The Lady’s Last Mistake by Cara Devlin

For years, Lady Cassandra Sinclair has harbored a scandalous secret and a painful loss. Unwilling to trust a man again, and determined to remain single, Cassie throws herself into a confidential project—a private home for pregnant, unwed women. Hope House is now her sole purpose. But after she is seen there by the arrogant lord she once fought feelings for, the walls around Cassie’s secret life begin to crumble.
Physician and fourth son of a marquess, Lord Grant Thornton is content with his reputation as a debauched widower. No respectable lady wants to marry a rogue, and after the tragic death of his first wife, Grant has no intention of marrying again. But his father’s impatience for a male grandchild to carry on the family title spirals into a demand that Grant either remarry and aid in the effort—or be cut off. When Grant discovers Cassie operating the much-whispered-about Hope House in the poverty-stricken stews of Whitechapel, he’s as impressed at her daring as he is furious. He also sees a wicked opportunity…