Good question OP.
I think at the end of the day it comes down to her view of your relative value.
The better of a match she judges you, the more she will acquiesce to your demands. For example, if you are a famous rapper, your main girl will probably openly accept you having side bitches. If you're not, maybe best to hide those side chicks lol. If you a completely average man, you may find yourself in a provider role with limited leverage. In fact any intimacy and association you get from women may be contingent on providing; obviously a weak position to be in.
Edit - also you'll probably have to be providing both the alpha and provider value for her. Even a girl casually banging a famous celebrity won't upend her life for him unless there's a good possibility of commitment.
So to OP - you can consider how important the move is, mention you're considering moving for work, feel it out, and see how down she is. Right away may be hard, maybe you plan for it in the near future. It's gonna be a pretty hard sell if you're not the absolute best guy she's ever had; plus she's weighing this against family and friends being nearby, important social support systems for women.