
MUCH more effective to ask him himself if he’s single. His friend may feel honor-bound to say he’s single even if he’s not. And yes, it still applies even if one or both guys are totally faithful in their own relationships; you err on the side of leaving your bro that opportunity even if you don’t think he’ll take it
OP, I for one respectfully disagree with this last part. If you DO have a boyfriend, your potential sidepiece might rather go in knowing about that. Personally, when I find out a girl I’m already hooking up with has a man, I get pissed she didn’t tell me herself, or tell me before we slept together So, lack of consensus here. Use your judgment I guess