Either he's a business man and he's at some conference for the weekend. Maybe he's out for drinks with a coworker or he ends up at a club. He spends the night with a man while he has a wife at home. But things aren't that easy. He is in the closet but no virgin to men. Would love to explore something with confusion/emotions and not just smut.
Or he and his wife want to spice up their sex life a little and meet with another couple. They set the rules and explore. Only that the guys are having so much more fun together.