oh i thought heavy-romance genre is somehow related to threesome or mistress XD
1. i'd like to recommend you some lovely Japanese Dorama like Itazura na Kiss: Love In Tokyo, Minami-kun no Koibito, Switch Girl or Good Morning Call.
for K-Dramas, maybe I'd recommend Something About 1%, Marriage not Dating or Because It Is My First Life and Whats Wrong With Sec. Kim
2. for rich woman themed, maybe I'd recommended Innocent Guy, but it was melodrama and the story so angsty. so i guess it wasn't your cup of drama. the one that i've been enjoyed lately is Game Sanaeha, it still on-going and the story quite good. the other one is Leh Nangfah. the story its quite cute.
but idk if you also enjoy Thai drama.
3. My Love From The Star, and Tomorrow With You.
for Thai-Drama, there's Kluen Cheewit, Paragit Likhit Huajai, or I Wanna Be Superstar.