You're asking for intense passionate, and not just, sex scenes in Asian drama series. Well, that's like asking for the impossible :) Why not try some movies?
@GertrudBB mentions Call Boy (2018), I second that. It's an intriguing story about a young man who feels somewhat empty inside. He learns to feel again, finds his purpose as a male prostitute, connecting himself to the passions of his clients, men and women, old and young;
Untold Scandal (2003) and A Frozen Flower Director's Cut (2008) are both loosely based on Dangerous Liaisons, the last one has a gay couple, the sex scenes are passionate in spite of the unhappy ending;
My P.S. Partner(2012) has passionate and hilarious phone sex, if you like that kink, the real thing is less hot imo, but it's there;
Mischange (2013) is a fantasy tale about body swapping. When an unattractive lawyer swaps bodies with his Don Juan friend, he finally can shag his female colleague. She had him pining for ages, but she longs for his friend. A bit pathetic maybe, but their sex scene is intense;
Love Lesson (2013) is a sloppy story about an older woman introducing a teenage boy in the world of adult sex. The boy is eager and passionate alright, whatever her feelings;
Obsessed (2014) is about a clandestine affair, not everybody's cup of tea. At any rate, the sex scene in the car is passionate;
Empire of Lust (2015) has lots of sordid sex scenes at the court of a mad king, but the story arc about his middle aged supreme commander is worth wile. He knows he will be vulnerable for his enemies, when he hopelessly falls in love with a younger girl. She's on a deadly mission, perhaps that's why their sex scenes are intense;
Okay, one drama series, with an honorable mention. Taiwanese series Marry Me, or Not? (2015) seems to be a romcom at first sight, but has a really original story. Keep watching until the end, you'll be rewarded in episode 14 or so.
Enjoy :P
