Once is Never Enough by Delilah Devlin

Mondo Acevedo is a legendary Dom and Master at the La Forge club. He’s helped his Memphis PD friends navigate the BDSM world and find the women of their dreams. Now, the vice cop and Dom is the last single man standing. But Mondo’s waiting for the right woman, one strong enough to match his dark passions, and he’s sure a timid grade school teacher definitely won’t make the shortlist.
Sunny Boudreau is content with her somewhat vanilla life, But when a trio of lovers moves in next door, she’s drawn to them and their group of friends, especially a certain tall, dark, and dangerous Dom.

Mondo tries to warn Sonny off, but her first taste of the club only whets her appetite and ignites her desire to prove she’s exactly the woman Mondo needs.