I totally see your point. The game so far definitely focuses on the supporting cast's sex lives while the player is on the sidelines.
The distinction I'd make though, is that it feels more like following along a TV drama(it is a mix of visual/kinetic novel so) than playing an NTR game(which I don't like at all either). When you watch a show, you see characters kiss or sleep together, but you don't feel personally cuckolded because you're an observer watching their story unfold.
That's what I'm trying to go for. I think the classic NTR feeling comes from when it's your established partner being taken, which won't happen here, I promise.
That's the way I view it though and each person's perception can be different, so thank you for perspective, I appreciate it.