In both films, the protagonists unintentionally end up needing to take care of a girl, and throughout the story they become their adoptive fathers.
Rough around the edges MLs with criminal pasts who turn their lives around because of a girl, "Man in love" is more of a romantic kind of relationship while "Lighting up the stars" is more of a father-daughter relationship , both slice of life dramas with a lot of deaths in them, both are tearjerkers...and they also have a similar vibe.