rnch saidso if either/both of you wandered off from the other, struck up a long conversation with a cute guy, leaned in, smiled, touched, hugged and kissed this other guy...you would be ok with that...since he is your bf and he's "just talking"?
Ah, now that's a different element you've introduced. But to your original question, of loyalty vs. hovering in not leaving one's side, I could also call it love. And a lot depends on the place & circumstances.
Last night we were at a fundraiser, where we knew most of the people there. Just like at a private cocktail party in someone's home, my partner & I hardly saw each other all night. We were socializing and visiting with people we see far less often than we see each other every day. And most of the partners at these functions behave the same way - they don't stick to each other like Siamese Twins. But perhaps partners aren't the same thing as BFs for your question.
When a former BF & I would go to a local gay club where we knew most of the others we'd also split off and go our own ways to visit. We'd get back together for some drinks & dancing, compare notes & gossip, then maybe split again. We were very confident in each other, not worried what the other was doing.
Yet when this same guy & I visited gay clubs during out of town trips we'd hang together the whole time, mainly because we didn't know anyone. We were friendly to others (so friendly that sometimes we'd go off-premises briefly with another couple for a quick 4-way
), but ordinarily I think we sorta "circled the wagons" in an unfamiliar place.
So that in your OP, I think it is "acceptable behavior to leave him and walk around the bar, saying hello to other guys you know and chatting them up." Provided you both know guys there, neither of you made a bar orphan. Otherwise one of you should be introducing the other around, just as a matter of considerate behavior.