The Bounty Hunter by T.J. Land

Together, Osiris Vanguard and Bobby Macintosh are the most infamous bounty hunting team in the solar system. Osiris is the leader, an ex-soldier who values discipline and efficiency above all else. Bobby, on the other hand, is a shameless scoundrel who nonetheless keeps their spaceship running and keeps Osiris from working himself into an early grave.
For two years now, Osiris has had a secret crush on his partner. Very secret. He’s a professional, after all. It’s not professional to fall in love with your co-workers. Besides, Bobby may not even be into men.
What Osiris is about to find out is that Bobby also has a secret. And it just might get them both killed.