Because we all know so many age gap romance manga/manhwa involve high school students 🙄 Anything over a 4 year difference meets...
A non-high school love list. College students, office workers, married life, etc. Supernatural elements may be included.
The following series all showcase a relationship between two leads who are in a different age group/have an age gap. [Both leads in these series are adults. Additionally, fantasy age gap series are also included]