I didn't mind the twist. It was nice to see Raymond catching up to the days of old (the stats of "present" getting ever closer to the stats of the "past", even far surpassing some of them). I also liked the blindfold setup, having an FMC who already got fucked by both NTR chads years before she met the MC.
Here's the issue (for me): If only the FMC had a relation with our MC to begin with. He never confessed to her, he never mentions a romantic interest in her, and even after he sees the FMC making out with Raymond he decides that playing it passive is the way to go (the worst trope of all, "she would never be interested in another man than me"). The FMC and MC never kissed, they never held hands, they never went on a date from all I know. That's what makes the NTR flaccid for me. The less of a bond the loving couple has, the less impactful NTR gets. I'd go as far as to say Arieno didn't even cheat on Robert.