My turkey goal is to have a pair. My understanding is that toms don't get to attack the hens like roosters do. They have to get permission (so no over sexing) A trio will probably happen sooner rather than later.
Anyway, I plan on letting the "extra" one from this year's poults grow nice and big next year for Thanksgiving. The other BR will be the breeding pair, and each year whatever doesn't get sold will be sent to the freezer. My husband want s me to try fried turkey, so I guess a turkey fryer will be on the shopping list with the bigger roasting pan.
Your belief that a tom has to get permission is not really accurate and that belief could very well lead to your tom killing your hen if you insist on keeping just a pair and always keeping them together.
First problem that occurs with just a pair during breeding season is over breeding since the tom has no other hens to alternate with causing a bare backed hen. If you insist on keeping only a pair do use a turkey saddle on her during breeding season.
Once the hen starts sitting on a nest, the tom will take the fact that the hen is laying down as permission to breed. Of course the hen will be trying not to cooperate and injuries occur and in many cases the injuries can be fatal. Other things that happen are that eggs may end up being broken when the tom slips off of the hen. I have even known toms to destroy the nest and eggs in order to get the hen back into the breeding mode.
It is far better to have four or five hens for one tom. That way no one hen gets over bred and they don't all tend to go broody at the same time which allows those hens that are setting to sit in peace.