are you restricting the use of theme for number of sites or domain while purchasing?
Can you share more details about your question. I’m not clear about your question that you asked!
All licenses only permit use on one website/domain per license
You can use the purchased theme as many site you need but for each individual website/domian you have to purchase individual license. As @charlie4282 mentioned each license will work only for one end product (single website/domian).