Is this netorare? She seems to like the guy but ends up having to fuck the whole class and the teacher...

Base +6, JulienUk +5

it's not ntr

futaro doesn't like miku the same way, the two aren't in a relationship, and there's no focus on the idea of miku "cheating" or anything of the sort.

there's a single line of internal monologue where she wishes she got partnered up with him, but it's brief and she gets over it quick

Base +6, Allera2 +6, Kamianme -7, nanaya666 -6, Ineedanadult +14, Cmdrtimbt +6, Avalaon +17, Drontman -8, Majestic0117 +6, darkrider1 +9, heh...narto +6, SpiritOrg -8, (insert name here) +7, and 1 more...

Japanese (RAW): https://e-hentai.org/g/2785678/372bd63563/

Base +45, Bane13 +59