So far, the story I gathered:

I think it wasn't a flashback, the uke is currently sleeping with the guy that showed up in the last panel - ch 2 (he has a mole under the eye & is named Doyoon?) but I don't think they're dating since uke was trying to fuck someone else in Ch 1 but they ran away so Doyoon replaced him.

The ML seme is gonna start work at a cafe with his blond friend and that's where he's gonna meet the uke and then they'll probably get together? It also sounds like the uke has something going on? Like he said he slept a little bc he had sex so maybe he's like supernatural being that needs sex to survive or maybe he has a sex addiction??