A vocal minority.
The reality is that the only thing absolutely required for a story to be NTR is for the MC's lover/love interest to be stolen from them. The MC doesn't even have to be in the picture for most of the story for it to work. All that is required is for the FMC to be fucking and falling in love with someone other than the MC.
We all might disagree with each other about what we want to see from Harry in this story, but what we are really here to see is Laura betraying him. That's what keeps us coming back. That's what makes it NTR.
Harry's suffering is just window dressing. On the same note, having Harry move on and recover is also window dressing. Same thing for seeing him gut Luca like a fish. All of it is fine, but none of it is necessary for the NTR aspect of the story. It's a matter of personal taste, just like how you prefer your steak. Regardless of whether you want it to be rare (MC is sad), medium (MC cries while jerking off), or well-done (MC finds a nice rope to spend the rest of his life with), at the end of the day you still just want a fucking steak (The FMC's corruption and betrayal).