Romancing the Rogue by Lana Williams

One enchanted evening.
One irrevocable moment.
Two lives changed forever.
Caroline Gold is desperate to save her family from financial ruin with a proposal from a wealthy duke. But a misstep has her engaged to the wrong man–Richard Walker, the Earl of Aberland, a handsome but cynical rogue with barely a farthing to his name.
Richard spies for the Crown under the guise of a wastrel rogue and seeks revenge for a fallen comrade killed by a notorious villain. Offering for the beautiful Caroline creates an unwelcome distraction. Yet the desire he finds with her makes him wonder if a life–and love–is possible…but only after he claims justice.
Caroline quickly sees there is more to Richard than expected, and his kindness toward her ailing father melts her heart. Yet marrying Richard won’t save her family despite the consuming passion she discovers in his arms.
A French spy posing as an English lord is on the loose. Can Richard unveil the man’s identity and stop him before he destroys all Richard holds dear, including Caroline?