Nearly to ch 43 so I can answer this now finally. Byeong wan is his ex, I think…hasn’t said if they were in a relationship yet. It also hasn’t established when they were together. Somewhere during won’s college years and before grad school. At least I believe that’s what he’s doing now..couldn’t figure out if it’s a job or not based on ch 39. Hope this answers your questions.

damn i left this for too long i was ransacking my brain where the fjck did that byeong wan come from... i can't really remember and i can't be bothered to read it all over again. but am i right that he's just the adult lee won's ex? he's not from the high school right??? bc i don't have memory of him ><