Sore wa Boku no Ai ja nai
それは僕の愛じゃない
Kazunobu Haizuka, an editor at a publisher, was suddenly asked by his twin younger brother to help turn down a guy from an one-night stand. But when Kazunobu went to meet the guy, it turned out to be Yukihara, the author that Kazunobu is in charge of and his long time love!
(Source: M-U)