The Playboy I Married Runs Everything

Clarissa is in a novel and knows it. The part she has been given is the side character who exists to move the romance between the two leads along, and who is used up doing it. Her parents have arranged a match for her with a wealthy family. She agrees at once, then passes over the male lead, whose future in the book is secure, and picks Leonard, the family's known playboy, instead. Her reason is that the marriage will change how her parents see her and get the family fortune back into her hands. Leonard turns out to be someone other than the wastrel everyone takes him for, and she ends up looked after by the man who actually holds the power in that house.