I just looked into the patreon and damn, I have some new interest in this. You've improved so much on the render quality and the game concept is quite ambitious! Good luck on the project and really looking forward to its release.
I think the concept of basing the NTR/love routes on a "relationship" stat is pretty decent from a gameplay perspective, but that often comes with some flaws on the NTR paths. You need to intentionally tank the relationship, and that really softens the blow of NTR. For example, the MC would have to intentionally neglect the girls and do things like not complementing her when she asks if the dress looks nice. Silly things like that. It almost leads to a feeling of netorase rather than NTR from the player's perspective.
Although it might not be as elegant, just something a NTR toggle at the beginning sometimes opens up more possibilities for each route on how you can respond to each situation imo. It seems like the game is well underway already though, so I hope it turns out well for both routes