A man in his 30s who actively avoids marriage and dating, preferring to live alone with his cat, Kitty. He is highly intelligent, logical, and rational, though he occasionally loses his temper. He eventually becomes the roommate of Yoon Ji-ho.
A pragmatic contract marriage that gradually transforms into deep romantic attachment, ultimately tested by external pressures and internal doubts.
A maternal figure whose unexpected intrusion highlights the challenges of balancing marital independence with familial obligations.
A lingering ex-relationship that surfaces as a source of past insecurity, ultimately serving as a catalyst for Se-hee's emotional closure.
Nam Hee-bong is Se-hee's traditional father whose approval Se-hee seeks for his marriage.
Se-hee confronts Bok-nam's inappropriate behavior toward his wife, establishing a rivalry.
Se-hee integrates into Ji-ho's family activities, strengthening their familial bond.
Explore the full interactive character relationship map of Because This Is My First Life