It can be done either way - the choice is yours.
If you create a new account within Affinity, there’s no need to have a second email address, as it uses a dummy Affinity email and just links up that way. There’s a bit more on this here.
As long as both accounts are linked to the same Affinity account, then both accounts can be accessed in the same way. You can add team members to the Affinity account rather than the individual accounts if you wish - either way is acceptable. But likewise with your own account, if they’re added to the Affinity account, they can use the same email with multiple accounts.
Hope that helps?