Tougo Ushiwaka reunites with his childhood friend and first love Ren Ryuugasaki after about 10 years. However, Ushiwaka had been traumatized to discover that Ryuugasaki, who he had thought was a girl, is actually a guy with a fondness for cross-dressing.
Shounen no Hatsukoi wa Bishoujo ♂ deshita is a completed manga by Kobayashi Kina, first published in 2018. It blends comedy and boys' love. You can read all 16 available chapters of Shounen no Hatsukoi wa Bishoujo ♂ deshita online for free on MangaPulse; the newest is Chapter 14, added 2021-01-24. The series is finished, so you can read it from start to end in one go.