Better Off Wed by Susanna Craig

She’s an avenging angel…who tempts him like the devil…

If Miss Laura Hopkins desired a husband, her beauty, brains, and fortune would make it easy to acquire one. Instead, Laura prefers to put her charms to another purpose entirely. Using the alias Lady Sterling, Laura helps young women who have been mistreated or compromised by their employers. Some might see it as theft and blackmail. For Laura, it is a small measure of justice. But while in pursuit of her latest target, Laura is unexpectedly aided by a gentleman who announces that he is Lord Sterling.
As a spy for the Crown, Captain Jeremy Addison, Viscount Sterling, has been assigned all manner of dangerous missions, though none as complicated as investigating the beguiling Lady Sterling. Forced to pose as newlyweds at the home of a disreputable earl, Laura and Jeremy forge an unexpected alliance…and a passionate connection. But can such a dangerous masquerade possibly lead to a real, lasting love?