I'm looking for a manga where the love triangle becomes a threesome and remains so until the very end.
I don't want a plot where one of the protagonists eventually steps out and wanders off into the sunset, but one where all parties are aware and accepting of the other two's relationship.
They don't all have to sleep together, but it's important that all three share meaningful or at least fairly friendly feelings.

Sadly, at least based on own experience, such stories are pretty rare and the only example I could find of one such relationship, is that of Gerard, Natalie and What's-his-name from Gerard and Jacques, short lasting as it was. (If worse come to worst, I don't mind having one woman and two men, but there has to be guy-on-guy action!)

Of course, no hentai-simply because I'm looking for an actual plot 😛
Thanks, all!

you know you want it

you could try Junk! Boys it has a threesome who are happy

Oh yes, these kind of stories are indeed rare. I can only think of some which may meet your expectations, but they're not the forever-happy-three like the previously mentioned Junk! Boys.

Ikenai Otoko by Takao Hiroi and Kamuro Akira. - It's pretty graphic (cause of the AV-industry theme). The three does not stay happy together, but the lovely "third wheel" surely likes the others very much, he continues being their close friend, and yummy threesome action also occures in the manga. ^^

Nibiiro no Hana Gou by Watanabe Asia. - That's a brothers threesome!! Not much plot, but it's not pointless smut. Tthe incest is explained with the mythical past of the family (I liked it^^). And my God, the art is purely A.W.E.S.O.M.E! Well, at least I really loved it. Watanabe's best work for sure. (Note that it's an original doujinshi title, so actually there's no 5 volumes but 5 long chapters. 4 of them are scanlated.)

Honeycomb Child (a oneshot from Rakuen Pet) and it's sequel Honeycomb Child dj - Honeycomb Child by Watanabe Asia. - Hmm, I'm not sure it's exactly what you want (I can't say they stay happy together, and Honeycomb Child is more like a twisted foursome), but try it out. The dj "Honeycomb Child S" is more like what you're looking for, I guess. (Strong traces of twincest, be warned!)

Name of Love and Hydra by Miyamoto Kano. - They're not threesome, the charas don't all sleep together but there's a guy in both stories who has sexual relationship with both the others and they're close, very close friends. And I'd even say at least one of the three guys are in love with the others in both mangas.

Flowers and it's dj Flowers dj - Flower Children by Miyamoto Kano. - Ooh, I consider this just exactly what you're looking for! Even though the three never actually sleep together. But not a fluffy story. ^^"

And maybe Nounai Ren'ai no Susume by Hiiro Reiichi, too. The protagonist has MPD (Multiplex Personality Disorder). It's like a parody of the actual illness so don't take it seriously.

The protagonist guy and his other two personalities all find different lovers through the manga, but they love each other deeply from the beginning till the end. (at the beginning they even have something like a self-sexual (?!) relationship.

Hmm, that's all I can think of. x)

Hard Core Heart. although it's so ridiculously happy that it makes me gawk. PWP

There's a one-shot called "1.5 Darling" in Baby Baby Baby that definitely has a happy threesome. Smexy twin butlers included! 😉

Thanks, guys, these sound great. 😃

you know you want it

The one from the Bachi-Bachi oneshot looks pretty happy to me. ;3

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