I agree with you on the result, if not fully on the way there. The MC and Ariana decided to explore their kinks, so far so good, that is still netorase. BUT over the run of the current version it becomes clear that the MCs´girlfriend goes well beyond what they agreed on.
She is now more into it for herself, her self-excusing stuff she does as "exploring". Most of what she "explores" is plain cheating, not netorase. It is just towards the end of current content that she gets at least some doubts. But there is not much netorase anymore, that is mostly NTR now. Which is sad, since it started quite well netorase-wise.
There is a reason I mentioned in an earlier post that if the MC´s girlfriend does not decide to stop her cheating, the MC and Queen should get a second chance, because their first try at getting together was a comedy of errors, wrong assumptions and wellmeant, but in the end bad advice from friends.