All beautiful starts have to have endings too, and they always happen in the most unexpected ways.

Jungkook and Taehyung's end come when Taehyung dies in a car accident. It's all unexpected, of course it is, and Jungkook feels like he's going to sink to the deepest pits of the ocean. Jungkook is drowning without Taehyung.
But he manages to still survive, Jungkook is strong, he doesn't commit suicide than most do. Jungkook dies all peacefully in his sleep, and he's happy to finally join Taehyung in the never-ending sleep.

It doesn't go so well for Yoongi and Jimin.
Yoongi gets sick, and nobody knows what is actually happening to him, they can't find a cure for it.
Yoongi has a painful death, which he never even deserved. And Jimin soon follows him, he does what most people do after losing their soulmate.
Jimin couldn't handle it, the pain, even if he tried. But that doesn't mean Jimin is not strong because hell, Jimin is strong. He was always there, for Yoongi, when Yoongi wasn't and was sick.

Everything is "normal" for Namjoon and Seokjin.
They both have a peaceful death, without any sicknesses or worries.
Seokjin once said that he knows he and Namjoon will die like that, all peaceful. Nobody really got it, how could Seokjin just know something like that, when he clearly can't? 
But it happened, and their deaths weren't even a week apart. 
That's what they always said about Namjoon and Seokjin; they will always be the strongest couple, the ones that will never let go even if you had the chance.

And Hoseok watches it all because he knows how the rest feel.
Hoseok's start is beautiful and so is his end.
Hoseok told the rest about his soulmate, how they weren't there anymore and they all understood him, why wouldn't they?
Hoseok dies when the sky is clear and full of stars. He used to call them his brightest star, so it is almost like he dies under their watch, they're finally taking him away.

Endings come, new starts come, but all of their stories will be remembered in a way.
They might disappear from some things but they will be remembered somewhere.

-

"I really don't care about the colours."

"Why? Aren't they the main thing in this whole 'soulmate' thing?"

"No, they aren't. You are. You are better than every single colour. I would let my whole world go to black and white if I could still be with you. You are my colours, you finish me in a way I can't explain."