Double Entendre by Katherine Rhodes

Matters of the heart don’t care about the rules…
Detective Simon Garabaldi’s simple belief that everyone deserved justice had endeared him to the kinky underground community of Pittsburgh. He was the one they trusted with their entanglements with the law, and he made friends with the people who played in the dark.
His life, though, seemed a more of a mess than anything he’d witnessed at the club. With his wife asking for a separation, he felt lost and confused.
Vanessa Carmody—Vanity to her friends and clients—was a hard masochist. She adored pain and knew the rules at Club Imperial didn’t even allow her favorite toys on premises. She was one of the best switches at Club Imperial, but her desires were rarely completely satisfied.
When Vanity and Simon collide, they find everything they want between them.
Or, so they thought. When a complication finds its way between them, they’ll have to figure out what they really want out of life, and out of each other.