As per our terms and conditions, if you purchased a personal plan (One site License), you can only allowed to use the theme on one site and you will get support and updates for only one site. But, if you purchased Developer plan you can use theme up to 10 sites and get support and updates for 10 sites. So, please choose the developer plan if you want to use theme more than one site.
For automatic updates, please activate the product key.
Have a look here for pricing plans.
Hope you understand.