Koi Nante Shinai!

From September Scanlations:
While he cannot explain it, Udou Ryuuji is absolutely certain of one thing: he loathes Kujou Ritsuki from the very core of his being. There’s just something about his good looks and the way he flirts and has all the girls eating out of his hand that pisses Ryuuji off royally—so when he accidentally discovers the deep dark secret behind Ritsuki’s part-time job, he’s of course going to milk it for all it’s worth…right?