Most Helpful Guy
I don't get his ideas one bit. Been to several bars in my life. Guys let other girls alone if they see they're with another guy (part of guy-code). You might get visually checked out, but that's about it.
I agree with several others, he may be going there to see another woman. Let him go and then show up about an hour later. Try to quietly slip in and check out what's going on.
Most Helpful Girl
He's being controlling, plus it sounds like he just wants to be able to check out other girls in peace. Or worse.