This happens to me a few times each week.
I'll be managing in the bar, when in walks one of my BF's with her new beau for the night, out for a barhop.
I always try to shake hands with guys when they enter the bar & I politely say to the girls...hello miss.
One of the funnier experiences for me was I had a girl leave my room at 3pm one afternoon.
She walked into my bar at 9pm with her new fella.
I introduced myself to the guy & I did the hello miss thing to her.......the fella said to me....this is XYZ & of course I had to say...nice to meet you XYZ 555555555
When I'm out on a barhop & I see a previous BF with a fella, I usually let the girl make the first move.......Like someone else said, you'll get the cheeky smile from her when the fella goes to the shitter.
It's also alot easier for me now being a papasan, cos I have had girls say to their fella's, that I'm Daddy XYZ from XYZ bar & that's how they know me.