Gosh, this is a tough one. I'm not really good at remembering who fell for who first. But rummaging through my brain i stumbled upon some titles. I'm just not sure if they meet all of the mentioned creterea above. So here goes:
Soulmate
That Fool
Ho Goo's Love
City Hall (not sure about this one actually)
Queen In Hyun's Man (totally fullfils the creterea of the calm and smart male lead. but not sure if there is a struggling)
My Father is Strange (family drama. The Pairing of the middle sister with the actor meets the creterea. well, even though i wouldn't call him calm but...emotional in a funny way)
9 ends 2 outs (friends who always miss the right timing)
Falling for Innocence
Cheese in the Trap
I Need Romance 3 (It's really good and meets all of your creterea but... it is a noona romance)
Unrequited love season 1-3 (maybe, haven't seen that yet. But it seems like worth a try)
Nobuta wo Produce (more friendship but the love develops over time)
In time with you
Because it's the first time
Because this is my first life
20th Century Boy and Girl
A Gentleman's Dignity
Bring it on, Ghost
Heart to heart (liked it alot. It's more mature than your average kdrama. I'm not sure if here was a struggling on both sides)
Mou Ichido Kimi ni, Propose (mature theme. no fluffines in here. But totally worth it. loved it.)
Nigeru wa Haji da ga Yaku ni Tatsu (one of my all time favorite. "Because this is my first life" is based on this drama but they are totally different. So you can watch both^^)
Stars falling from the sky (can't remember if he loved her first or the other way around. Sorry)
Holymoly... there sure came out a lot. I hope i could help with these^^