Young-Ok met Cheol-Ung in Gangneung at age 22, whom she dated for two years. Cheol-Ung could sing and play the guitar well, but, to her dismay, he would transform into an unpredictably different person when drunk, as per Young-Ok's description of him. And while he never physically lost his cool with Young-Ok, or any other woman, for that matter, he'd get into violent altercations with other men when intoxicated. When he picked a fight with a passerby one day, Yeong-Ok herself reported him to the police and later broke things off with him, leaving Gangneung.
Based on the portrait she paints of her time with Cheol-Ung, it appears he'd still be hung up on her since it wasn't a mutual breakup. And the erratic texts and phone calls do seem to align with his volatile nature. After all, Young-Ok calls him a "total thug" when defining his character traits. Could it be him who relentlessly keeps attempting to get back together with Young-Ok every now and then? While Young-Ok seems bothered by any contact maintained by this unidentified person, her reasons for not fully cutting ties might come to the forefront as we head deep into their story with upcoming episodes. Moreover, episodes 13 and 14 are titled "Young-Ok, Jeong-Jun, and …," which suggests we'll delve into this mysterious character during those episodes.