Found, One Wife: Finders, Keepers (Harlequin Superromance No. 809)

That was the ad, and Noah figured if he'd been adventurous enough to discover the world, he could be adventurous enough to visit an agency that specialized in finding lost loves. But meeting investigator Maggie Tyrell was an adventure in itself. Noah soon discovered he was less interested in finding Sisela- the woman he thought he loved- than in finding out more about the fiery self-styled love detective! Maggie refused to be convinced. She also refused to be deterred from the task she'd been hired for-even if Noah wanted her to call of the search.