The ultimate scenario for us was when a married coworker (soon to be her boss) my wife was interested in turned out to be everything we'd hoped for. He wasn't afraid of a relationship with us, and he knew how to take care of her when they traveled together, as well as when they were in our bed. Perhaps most important, he knew how to play it when family or other friends and coworkers were around. It's no different than a traditional marriage relationship, I'd say, it takes some work and commitment to make it all work. And some flexibility!