No, there’s no NTR. None of the women cheat on the main character or get taken from him.
What people probably mean is this: there are a few optional threesome scenes. Most are FFM. One on Maya’s route is MMF, and it only happens if you tell Maya you don’t want to be exclusive.
You can turn all group scenes off when you start a new game or anytime in Preferences. When they’re off, those scenes don’t happen at all.