I'm sorry, y'all... If there was a way to give people discounts based on their previous purchases then I would do that in a heartbeat!
Edit: There was and this was fixed!
Since the answer is "Yes, you'll have to pay for each and every update regardless what you've already paid", there's no incentive to purchase updates, it's better just to wait for the game to be finished before buying it then. I know I'm not planning on paying for each and every chapter, especially since you're now splitting up the chapter updates - making us pay full price for each half-chapter update I assume.
It's too bad, because I've enjoyed the game so far.
The update was cut in half because it was too big and was taking me too long to release. Chances are that the second half won't be as long as the first, and if that's the case, then I probably won't be charging as much for that update. I usually detail these kinds of things in my weekly reports to keep people updated along the way, though the reports are on hold for holidays/launch week at the moment.
Also, technically, I think my answer is closer to "All I can do is work within this website's shop system. I can't control how they allow developers to charge for our games, and I'm far too poor to put updates out for free." From what I've seen, it's pretty common on this website for AVN devs to charge for new updates, especially updates that they've worked really hard on. However, if you choose to move on then I understand, and I appreciate the support you've given so far. Again, if Itch had a way for supporters to pay a smaller price to upgrade their game to a new update, I assure you, I would do it! It wouldn't even be up for debate!
(No hate intended with the words above!)