there are ways to go around, there is an option to skip the sex scene with Shakala and the goblins, and you can fight Grug, so i don't know why you are complaining about it, the NTR stuff can be skipped.
When you dedicate Zivahs temple, the MC is forced to have threesome with her and Grug.
As for others who've commented, the reason why I personally use the NTR label so broadly is because there is no other catch all term for "MC's love interest being fucked by another guy." Its the closest thing that fits as typically in games, this action falls into NTR territory. Not always mind you, I have also seen plenty of Devs try to include the Li/other male content while skirting the literal definition of NTR, with statements like "well no, its not NTR because they arnt in a formal relationship with the MC, you can't get mad at NTR because its technically not." Like come on, its the same damn thing, you're putting the scene in the game of another male fucking the Love interest to invoke an emotional response of jealousy from the reader, quit splitting hairs here, that's NTR in everything but name.
I'm not a fan of sharing love interests with other guys. Whether it is sharing, swinging, group sex, or straight up NTR. I just don't get why he'd Tinkerer wouldn't include a choice to avoid that scene like he did with Shakala and the goblins or Mia and the werewolf? This game would be fine if he just included a choice like he did with the others.
I'm sorry if I come off as an asshole because I word things strongly. At the end of the day, its just a game and I myself skipped past it as quickly as possible and moved on to fucking up the country side with the succubus daughter. I just have a strong dislike for that type of content when it's forced on me. I'm all for people liking what they like, so long as I don't have to deal with it.
Edit: Quick aside, I personally dont care if it makes canonical sense for a female character to cheat or sleep around, or have other lovers, ect. I'm just a territorial asshole who wants all the woman for himself. I hate sharing and no amount of rationalizing will get me to be okay with it. Hell, I'd happily murder every other male character in the game just to make sure there was no competition if given the option, friend or foe, story be damned. In the case of Zivah, I get she's a sacred prostitute, her religion is all about spreading free love to everyone. I just don't want to share so I personally would prefer to be able to just ignore her completely now she's proven she's fucking other guys. I'd also prefer to be able to get Calithe(sp), the young swamp elf we rescued, the hell out of that temple before she's forced to whore herself out. Set Cailthe up in one of the MC's many home bases. perhaps pair her up with our High elf lover near the well. I know it wont happen and both her and Zivah will be taking giant dick left and right when the MC is away, but she's a super cute character so I hold out the tiniest of hopes.