I am looking for manga in which the protagonist is the third person in an existing relationship, something like Strobe Edge or Heroine Shikkaku. Actually I prefer the protagonist to be the third person in a marriage, but any kind of romantic relationship is fine.

Anything is fine with me, except for hentai. Thank you!

Ah, you already mentioned the one I was going to put down first, Strobe edge XD
Skip Beat!
Honey Bitter*
Ao Haru Ride by the same author of Strobe Edge
Show Princess
Papillon - Hana to Chou*
Black Bird*
She Is Mine
Absolute Witch
Shounen Dolls
Masca*
Maerineun Uibakjoong*
Suki-tte Ii na yo*
Scarlet Palace*
Kimi wa Pet*
Mars* at various points
Ten no Ryuu Chi no Sakura
Bitter Virgin
Red Lion

* = actually in a relationship.
The rest are all two people falling in love with the same person or two people who are in love but no an "official couple", as it were, with a third person.

________________
I am the master of my fate;
I am the captin of my soul.
William Ernest Henely

I rate manga with 5 being the average score.

I recommend Koibana! Koiseyo Hanabi. The main guy has a girlfriend when the heroine falls in love with him.

________________
“All the kids have always known,
that the emperor wears no clothes,
but to bow down to him anyway,
is better than to be alone.â€

-Arcade Fire

Thank you for the recommendations!

I'm still looking for more recommendations for manga with third-person protagonists 8D

Datte Suki Nandamon

________________

currently reading: Nyotai-ka
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