Recently I've gotten bored with the usual  "puppy love" that's in kdramas and other dramas I've seen, I'm in the mood for something more grown up, adult, and steamy right now in the romance or romantic comedy section of kdramas (it can be none korean as well) so please right down your favorites in the discussion! If you could write a brief summary that'd be awesome!! Examples: Secret Love Affair (but less depressing) also the Taiwanese drama Devil Beside You :) Secret Garden maybe (less long of a wait, you get my lingo?) Ive recently been loving Kill Me, Heal Me (but I'm afraid it's gonna be pretty innocent) :( I dont know whats wrong with me? Lol, just leave your suggestions, thank you!!
It's ok that's love
Secret
Master's Sun...may take long but dialogue is adult at times
Witche's Romance
....there are movies but those are def. steamy and rated R
Dramas are mostly catered for family/mainstream viewing so there won't be many 'steamy' dramas around. If you want something more adult & steamy you can find it in movies which I can recommend a few (as long as you're 18+ years old)

There is one K-drama I've heard that's considered pretty steamy (there's only 4 episodes). I haven't watched it myself but you probably find scenes in there you won't find in regular dramas: http://mydramalist.com/8224-temptation-of-eve

If you want to see dramas without 'puppy love' and couples who act like adults in love I can recommend:

Lovers 
http://mydramalist.com/1069-lovers-2006