Emma and the Earl by Samantha Holt

With a duke and a viscount for brothers-in-law, Emma has found herself subject to increasing attention from the many eligible men of the ton. A new experience for this redheaded, freckled bluestocking, who would rather be doing something else—anything else—than dancing with men who are only interested in her connections.
Marriage is not for her.

At least it was not. Until a certain Lord Radcliff—and a true rake—decided to accidentally ruin her. Well, perhaps neither of them quite envisioned ending up twined in such a mess that the only way to save her reputation—and that of her younger sister—was to marry the man.
The Earl of Radcliff is a practical stranger to her but she is prepared to make the best of her situation. After all, she is nothing if not a quick learner. Perhaps she can learn to be a successful wife and countess.

Unfortunately, the earl is hiding a few secrets. She’s not sure what they are but one of those secrets is causing a strong hatred of the country, and that just will not do. Emma hates London and is prepared to do anything to remain in the country with her family and friends. Somehow, while dealing with all the new adventures and, um, desires a marriage can bring, she must persuade her new husband that the country life is for them.