The Fixer (City Slickers #3)
P. Mulholland

The handsome middle son of the infamous billionaire family. His job is to clean up dirt that may taint their good name, and bury skeletons that hold secrets. He is cocky and crude, sly and selfish.
When a mysterious, beautiful artist asks him to do her a favor, he simply can't refuse. She wants him to fund medical treatment for her 3 year old daughter, but to grant her wish she has to return a favor. She has to cheat on her husband and become Corey's lover.