Yeah, the mangaka confirmed it in the postscript. Plus, Daiki even said for Tatsumi to not bring up old crushes.
yeah but who is the random guy daiki had sex with before? all the time it was like him saying he never had sex with a guy and than he says he had Oo?
The random guy doesn't matter. It only seemed like he never slept with a guy only because he didn't dwell on it.
i think it was in the story of the lawyer he stated he doesnt go for guys XD he only had once a crush ( lawyer)
After re-reading this I realized I didn't connect this part of the conversation very well, but I believe it reveals Daiki once had a crush on Matsuno.
http://www.mangago.me/read-manga/before_daylight_love/bt/242514/Vol1_Ch4/33/