Romance With Age Gap?

High five for team Yoo Jin ;-)

Secret Love Affair - this is about as hot as tv kdrama gets
My Queen - Writing is weak but lead chemistry is so good it didn't matter
Long Vacation - Loved this.  Great Ost too.
Dal Ja's Spring

I Hear Your Voice 
Last Cinderella
Goblin (age gap of about 900 years lol) but if we're talking real I think he is supposed to be mid-thirties while she is 18 or 19

Thanks guys. I've watched I Hear Your Voice and Koishite Akuma, the rest I'll give a try.

Sweet 18, old drama but really worth to watch :)

Some different recommendations! All with older man/younger person.

Koukou kyoushi 2003 (j-drama, male teacher around 30 or late 20's/female high school student)

Koi (j-special, male teacher/female university student/wife, with a twist)

Mitsu no aji (j-drama, girl and her not blood-related uncle)

The Painter of the Wind (k-drama, crossdressing female young art student/male teacher - historical)

Utopians (HK movie, male university student/male student - there are sex scenes)

My Rainy Days (j-movie, university teacher/high school girl)

Beethoven Virus (k-drama, male conductor/female orchestra member, not huge age gap but still)

Valid Love (k-drama, male teacher/female high school student, but most of the story is later when she's older but the age gap is still there of course!)

Iki mo dekinai natsu (j-drama, 40-something man/19-year-old girl, but the romance is mostly between the lines)

Battle of Changsha (c-drama, man around 30/16-year-old girl, amazing drama)