So I remember that in the story there was a girl who was an exception in the place of carnivores, she was the only herbivore. She used to study in a school full of carnivores and then a guy also falls in love with her but then she has to change places and goes to a boarding school where both herbivore and carnivores reside. I remember in this story there was a misunderstanding all this time. The guy could only love once since his species was of that kind, kinda like werewolf mate stuff. So when he comes to her boarding place he ignores her, treats her nothing special and stuff like that.
Thank you if u can find it. 👍🏻 😁

Monokuro Shounen Shoujo - first thing that came to my mind, though it probably the wrong one.

Ooh this looks good but i actually found it, it was

This Wolf Won't Bite
https://www.mangaupdates.com/series.html?id=184612

Thank you though
(*ˊᗜˋ*)