The author mentioned in the author's note after season 1 (that's not translated) that Jowoon has had multiple relationships with women and slept with them. Only guy he's been with is Heasoo.
It's not shown more like lightly implied but the author said in her q&a that joowon does date other girls and while haesoo is open about his relationships joowon tends to be private about them to haesoo. Unfortunately the q&a isn't translated but Twitter and ig have ppl translating.
Oooh thanks guys that’s so interesting! Would never know if not for y’all xD
I don’t remember if this was mentioned or shown before in the story, but does Jowoon also sleep with guys other than Haesoo? Or girls?