An Unlikely Countess by Alyssa Clarke

#opposite attracts
#Accidental compromising

Miss Julia Fairbanks feels adrift as her siblings marry and find their happily ever after, leaving her yearning for a love that sets her soul on fire. Determined to savor her season, she quickly grows disillusioned—until a dangerously tempting encounter in Hyde Park with Rafe, the Earl of Ashton, changes everything.
Rafe awakens a desire in Julia she never anticipated, but he has his own ideas about the perfect wife, and she doesn’t fit the mold. However, when a compromising situation forces them together in the most unexpected way, Julia finds herself waging a bold campaign for the aloof earl’s heart.