Oretachi wa Shinkon-San Kamo Shirenai by Chishanomi

Summary

Plot: “Should we just go for it? Marriage?”“…That’s it!”Love that blossoms post marriage can be a thing too, right? Nasukawa, a pragmatic graduate student in science, and Kaburagi, an elite office employee, are university colleagues and very good friends. They’ve been living together to save money, but are told by their landlord, that two male friends are prohibited from sharing a room, so the two get married as camouflage. Nasukawa notices that ever since their marriage, his heart is throbbing for Kaburagi, who’s supposed to be just his friend.