Main lead couple with no rivals/other love interests?

Hello,

I'm looking for any dramas (romance hopefully) where the main lead couple don't have any rivals in love/affection, basically no messy love polygon, ex bf/gf that come back into the picture.

Something similar to the main couple in Love O2O (even though so many try to go for WeiWei lol) and in Goblin where both main and secondary couples have their own two-way relationships (no love triangles lol).

This will help: http://mydramalist.com/discussions/recommendation-forum/29486-sick-of-love-triangles

Soratobu Kouhoshitsu
Bring It On, Ghost
Oh my ghostess  
Descendants of the Sun
Legend of the Blue Sea
Madame Antoine
Mars
Nigeru wa Haji da ga Yaku ni Tatsu
Nodame Cantabile
Oh My Venus
Queen In Hyun's Man
Sekai Ichi Muzukashii Koi
Shopping King Louis
Tatta Hitotsu no Koi
Healer
Kill me heal me
Goblin
Boku, Unmei no hito desu

Thanks all, I actually finished Nigeru Wa Haji da ga Yaki ni Tatsu sometime ago :D

same with Boku Unmei Hito Desu (wish it had a slightly better last episode)