Responses
srry ff
Uhmmm idk if this was what you are looking for. But it fits to your description... i think.
http://www.mangago.me/read-manga/warau_kanoko_sama
And here's the sequel
http://www.mangago.me/read-manga/koi_dano_ai_dano
I'm searching for shoujo manga. (most likely an one-shot)
Heroine called herself "a secondary character" and helped her pretty friend to find a boyfriend. But after finding the right guy for her, he choose our heroine over pretty girl.
I hop someone can help! (๑•ㅂ•)و✧