This game as a setting option for NTR that can be set to on/off.
Do not flip that NTR switch on and off repeatedly. Set it once and forget it.
The way the setting works is that it prevents each character's NTR path from starting, rather than disrupting an already existing NTR path.
If you switch it on you can accidentally get an NTR path started for a character without noticing.
Turning it off again will do nothing as that character is forever marked as being on the NTR path and will never stop being so, barring a reload of an earlier save.
If you do not want NTR then set it to off and leave it that way forever.
if you want to play with it on, set it to on, leave it on, and pay careful attention to the walkthrough if you want to manually avoid a specific character's NTR path.
If you break your save, this is entirely on you. And there is no way to repair it if your broke it.