That's Steam's decision, which applies to all AVN's. Those can't be sold on steam in Germany and China, due to local laws. Our itch.io release is pretty soon though.
Belgium shouldn't be an issue. Steam's decision was "only" to restrict our game for China and Germany. Unfortunately there's nothing we can do about that. If it was up to us, we'd let the game be sold in all countries 🤷♂️