I found the book under tortured heroes section some 3 or 4 years ago. Blurb said that FMC takes a job from a rich lady and there she meets MMC who is also that lady's sex slave.

[Miss.]

So, the opening scene as far as I can remember was of the FMC landing on an airport and somebody came to pick her up, possibly one of her paramours. The FMC is super bitchy and bossy and she has two lovers in the beginning,
one she has sex with which is the scene right after the airport, and one she strings around. Both of them she treats as her leisure hour activities. She gets an invitation from this rich socialite and matriarch about an article or a book to write because she's a writer, who is also keeping the MMC as her personal sex slave. She doesn't believe him at first or that's what the blurb said but eventually does and pities him and tries to rescue him afterwards. She's a super flawed character and she constantly hurts the people around her with word barbs. She has a lengthy argument with one of her lovers, the one she strings around, and he basically points out her bitchiness to her and she returns fire and then she's off to meet the matriarch after accepting her job in a race car I remember, which might have been a convertible and red. That's where i stopped reading.
Thanks so much in advance if you know the title.