It really depends.
In our dyanamic-no dates until they meet both of us. That meeting doens't have to spell out anything-it's design is for each of us to be sure that the new person is fully aware of our full commitment to one another and to avoid people who think that if they are good enough, we'll end our relationship (which is unfortunately too common).
So, if for example you were going to date my husband-you would have to meet us both for the first face to face meeting. Usually we go for coffee -or hanging at the park or something. Not big. There's no big "required conversation". Just a hi, I'm so and so and I'm so and so and I'm so and so.
At times I've even left after 10-15 minutes and gone to do my own thing-giving them time to themselves.
It's not the same as "meeting the family" and the purpose behind it is to avoid the "cowgirls" (or cowboys-except I'm not dating and he's straight.)
"Love As Thou Wilt"