Dungeon series by S.M. Johnson [epub,mobi]

Above the Dungeon (Dungeon #1) :

With the ink barely dry on his Ivy League diploma, Dare is expected join the family business, marry his high school sweetheart, and commit his life to conservative suburbia. But in a moment of panic he runs away to NYC where his cousin gets him a bartending job at a club called Above the Dungeon. The basement of the club houses legendary BDSM Master Roman's dungeon. And Roman's interest in the newest bartender challenges Dare's lifelong perception of his own sexuality. As he draws Dare into the world of BDSM, Roman has to contend with the feelings and insecurities of Jeff, the 24/7 slave he has at home. Alternately told from points of view of Dare and Jeff, Above the Dungeon is a series of highly erotic BDSM scenes tied together with tight plot and intense relationship dynamics.

Out of the Dungeon (Dungeon #2) :

When reality interferes with fantasy... Club owner Roman has the perfect Master/slave relationship with his life-partner Jeff, and when they increase the eroticism of their play by bringing Dare into their bed, Roman has everything a man in his position could ever want. But when Jeff is injured in an accident, there's no time for dungeon play. Traction is like non-consensual bondage, and Jeff calls "red." You can take the Master out of the dungeon, but can you take the Dungeon Master out of Roman?

Three in the Dungeon (Dungeon #3) :

Is love enough to forsake power exchange? Roman and Jeff are building a new life in Minnesota, even though Jeff's been insisting since the accident that he just wants to be vanilla. A funny thing, though, Jeff's BDSM erotic fiction is quickly becoming the latest Amazon Indie success story, which makes Roman wonder… if Jeff is still kinky in his head, what about his heart? The local fetish community is a lot different in this town than in the club Roman created in New York City. Roman admits that he's a fetish snob, but still, an inexperienced local boy has managed to capture and keep his interest. Roman is determined to integrate his own controlling tendencies, Jeff's imagination, and Jason's submission into something that feels like home.

Dare in the Dungeon (Dungeon #4) :

"I dare you to leap…" Kneeling for Thomas is like skirting the edge of a fatal fall, and Dare wonders what he's gotten himself into. Why can't he just be happy with Zach, the perfect gay boyfriend? Yeah, Zach forced him out of the closet, and that was uncomfortable, but that's nothing compared to what Thomas expects from him. Subbing for Roman was cookies and milk and kindergarten naptime compared to this. He wants to trust Thomas and stop pretending, but how much pain and humiliation can one Ivy League kid handle before he comes apart? Meanwhile, in Minnesota… Jeff continues to write hot, hot, hot D/s erotica while battling emotional trauma from the accident. It's easier to keep Jason as a buffer between himself and Roman than to face his fear of being tied up. He's tired of being broken, but how can he be fixed when he can't stay in bondage for more than fourteen minutes?