Even if you choose the main heroine to be slut there wont be NTR. It's basically just her behavior that becomes sluttier but she will not cheat on you. There's sharing content however this sharing is also of your choice, when you're prompted to make a choice, black stripes will appear on the top and bottom of your screen and often it indicates the outcome. The pure route she will be very much there only for you and wont bother knowing about others things unless it's special characters that even in pure route you can still chose to share her with them or not. While the slut route she is open to more thing like taking nude photos or accepting to be touched by others in the park or and gangbang in the starcon, but all that is ONLY and IF ONLY you choose so. She will never ask if she can do it on her own which means, you shape Anna however you like. I prefer to make her into the slut path but i dont share her or any of the others girls with anyone, making Anna my personal slut wife and the other girls my harem. This something that this game really did well it's how much freedom you have. As long as you dont touch the choices of sharing nothing will happen