I don't think your boyfriend should have the right to dictate that you can't go out with someone else unless he meets them, but to some extent his reason for wanting to meet the other guy matters. Does he want to be able to say "Nope, don't like him, you can't see him", or does he just want to get a sense of who the guy is and whether he's a safe person for you, and, as Hubby once put it, "be able to pick him out of a lineup"? (Hubby was joking. I'm not sure my then-boyfriend was amused.)
I don't have, and wouldn't accept any of my partners having, veto power in terms of saying "you can't see this person." I do have "veto power" in the sense of "you can't see this person *when I am present*", though I don't even phrase it that way, I say "If this person is going to be there, I won't be." To me, it's wrong to try to enforce or restrict something in a relationship you aren't part of, when it impacts a person who doesn't get to be part of the discussion.