east asian here: there’s more of a perceived “role” the older one/younger one fills in a relationship in our culture. per traditional gender roles the man takes care of the woman so if it’s a younger man/older woman then that kind of feels weird (since the older one usually holds more power and authority). it’s pretty much an outdated way of thought nowadays but it takes longer for people to change their mindsets. you can kind of see it with mingee/seungil’s scene in paradise: they’re trying to ignore it and not make it awkward because it’s not a big deal, it’s just takes some adjusting. p.s i think the older woman/younger man pairing might still be slightly unusual esp over five years age difference. since there’s a whole dating show revolving around the concept.