Koigakubo-kun Stole My First Time

Eiko Kagehara truly loves one thing in this world: the MMO she's played with her friends for the last 15 years, in which she leads a fantasy life as a sought-after blacksmith. But when her friends start leaving to, of all things, get married, have kids, find new jobs...she's thrown for a loop. So much so, in fact, that she drunkenly shares her gamer ID with her super-hot new colleague...who just happens to have been helped by her in-game in the past, and who wants to repay her by teaching her how to love?!

(Source: Kodansha USA)