There IS ntr in the game. You have sex with Gerda, while cucking her husband. You're the one ntr'ing others instead of getting ntr'ed. The dev said that the netorare content will come after most of the main path is finished. At the very least, you'll probably have to wait till the 3 mega updates are done, which would be like at 4-5 months.
Edit: The game is mostly about the MC's split-personality/inner-demon changing him after the accident, which is why the corruption/being-an-asshole path is getting the most preference. iirc the netorare content happens if the MC goes to the doctor for his checkup and cures his split personality (The option to go to the doctor is in the game, but is not implemented yet).