when do you think its ok for game to put NTR in it ?

[pharal]

Personally I don't like NTR as a tool to promote jealousy in the middle of a game with a character one has a relationship with. That said:
I think that if the DEV is clear an upfront about it, people who don't like NTR should stop complaining because they are not the audience then. They are not owed a non-NTR game if the tag says "NTR". People who give an obvious NTR game a bad rating for containing NTR should freaking stop acting like the center of the world and just skip it.
If the DEV introduces it later, I think it is fair to provide a warning. Again nobody is owed a non-NTR game, but I find it completely fair to rate a game based on a sudden change in direction, so it is in the DEV's best interest to be very open and possibly provide tools in-game (skip or setting to avoid) to mitigate bad ratings.
In short: Don't judge the fetish, but do judge the game direction if it were NOT a part of the plan in the beginning.

 

[The ArcKnight]

Honestly, this is going to depend on your tastes.
For me? Never. Fuck NTR.
But for regular people, I think if you make it avoidable and don't try to force it down someone's throat, then its whatever.
The key here is to make sure the regular content is just as good as the NTR content if you're trying to balance both.
If you're going to make an NTR game, just state from the start thats the purpose of the game. If you're going to make a harem game though and you introduce unavoidable NTR? Prepare for the flames.

But like I said, just make that shit avoidable, balance the time spent working on both, and make both paths equally hot and you'll be good.