I think the author made som rookie mistakes here. I think everything would’ve made more sense and worked out in a more satisfactory way if yujin just never had feelings for her. Cause i mean, while yeah she’s an adult now, he’s still known her since she was a kid. And not only that he actually had like a parental bond/role with her. And not blaming Moa at all for developing feelings like that’s just girlhood. But the story could have developed more like a “I’m maturing now and progressing means letting go of this crush once and for all”. She seemed to have a difficult relationship with her parents as well which is sure to leave some marks. Like I can see a lot of interesting themes there that would have been super cool and interesting to delve deeper into. But we got this.. but whatever, everything can’t be Shakespeare.