Nibanme na Boku to Ichiban no Kanojo

Story

Minamino Chinatsu is a beautiful girl who's incredibly popular and easygoing. Ever since I met her in the fall of my first year of high school, my life has been anything but ordinary. It all changed when another guy with the same name as me showed up at school – a handsome one, no less – and suddenly my classmates started calling me 'Number Two.' "You're not 'Number Two' to me," she said. "Besides, it's me who wants to kiss you first." My relationship with Chinatsu goes beyond just school.

Synopsis via AniList (English).