Choosing Nika will not affect anyone else than Nika scenes.
Thanks to both of you. I though that maybe being on Nika's route will be a problem some day if Juliana find out about the relation (and I think, if it's happen, she won't be as zen as John ).We don't really block content in that way, we more like reduce the amount of content you get with some characters based on if you skip or deny them, we don't penalize making a harem for yourself , we tend to make the choices quite clear in that regard to show interest or not show interest. Ending will be affected though in part by your choices as well, but again we don't really penalize
IIRC, Heather wasn't so keen with the fact that Gaz was seducing the MC, even if she's open to have threesomes with Juliana.
So besides Nika, any other girl that can have her content reduced and that we have to think of having an "exclusive" route ?we more like reduce the amount of content you get with some characters based on if you skip or deny them