Kanojo no Oshi ga Kirai

Synopsis

The problem with the handsome college student Kei Tachibana, is that his cute, older girlfriend Chisa is crazy about other men. What's worse is that these men are her favorite 2D characters. How will Kei-kun struggle every day to make Chisa care more about him than those blasted husbandos? This is a love comedy between a devoted younger boy and an otaku working woman! (Source: Manga Mee, translated)