Sorry to ruin it to NTR fans but NTR means stealing the heart of a girl or making her submit to you preferring the bull over the MC or actual partner, if they add a final bad scene where they get fucked by the other guys it will mean cheating or rape, not actual NTR, learn your tags.
And I don't think the author will have the patience and energy to made and entire love route/NTR where the girl falls in love or desire the other guy, it will be like a rape scene.
PD: As someone who used to enjoy NTR and now I'm more into romance, there is nothing to gain to have NTR, but since is going to be completely avoidable, Im not going to ruin my experience, the romance here is good enough.