Looking for a shoujo manga

Hi everyone,

I'm looking for a shoujo manga I read a long time ago. I'm sure it wasn't that good but I want to read it again. I think there were only about 3-4 chapters. I don't remember much, just that the guy love interest had the ring of the girl he liked or something, I think it was the school infirmary teacher. Afterwards he fell in love with the MC and I think there was a scene where they go to the pool or the beach and he was jealous.

Sorry that's not much to go on but can't remember much,

Thank you