Optional or not it will completely turn off a large part of the support of this game, and if you are not a ntr fan why suggest it then.
Viewing post in Fighting for Love (Free Adult Game) comments
I am a fan of good stories in general (I'm sort of a VN worm). If something doesn't make much sense in a story it bothers me (especially in movies) e.g. Naruto bothered me a lot when they killed off Madara in such a stupid way. That's all there is to it..... Also it's "an NTR fan" I apologize, truly (not being sarcastic).