I wrote this over a year ago and I completely forgot about it. Then I had a conversation like this:
Friend: You just love killing everyone's joy.
Me: About killing everyone's joy… How about I post this angsty malec fic I wrote a long time ago?
Friend: Don't you dare.
So, I'm posting it. Sorry.
Also, sorry for any mistakes, english is not my first language.

When you said your last goodbye
I died a little bit inside
I laid in tears in bed all night
Alone, without you by my side

Magnus woke up, instinctively reaching to Alec's side of the bed, only to find it cold and empty, the way it always was. With no one beside him to smile, to look at him, just to be. Alec was never there, even though he checked everyday. But the other side was empty, the same way it was yesterday, a week ago or tens of years ago. There was no one there.
(He really should get rid of this habit, of checking if he's still laying there.)
(He never is.)
He tried to move on, he really did. His friends tried for him, too – Catarina Loss has tried to set him up on so many blind dates in the past few years, he didn't even bother to count. With men, women, Downworlders, Shadowhunters or even Mundanes, she was pretty desperate, yet it never worked. Magnus just couldn't look at anyone longer than few minutes, he could never feel anything that was even a little bit similar to what he felt towards Alec.
(But he was gone.)
So he didn't move on, even though he knew he should. Being too tangled up in the past could destroy anyone, but for once he didn't care. He ended up living in the same apartment, accompanied only by his cat. And that was all.
(He couldn't forget, he didn't even want to.)
Maybe forgetting would have made this thing easier for him, less painful than it was. He knew that, sooner or later, it was unavoidable – even if he would never forget him completely, he noticed that some things were already blurry in his memory. He's got a lot of pictures in his house, hanged up on the walls, but they all represent a split second each, just a little bit of the whole thing. And it's the entirety that really matters, in the end.
He started to forget the sound of Alec's voice, and now he just couldn't make himself remember it. The way he used to move, gesticulate. The way he laughed, the way he smiled at him. The taste of his lips. The feeling of his hands against his skin. All the little things that used to make him the person he truly was, that couldn't be captured in any photo.
(It absolutely terrified him.)
What was left now, was just the overwhelming love he felt towards him, and that he was certain he would always feel in some way. There were blur memories, that were fading and he didn't know how long they would last.
(But that was not enough. It would never be enough, because he could never get enough of him.)
The thing he couldn't forget was the day it all ended. He remembered Alec laying on the bed, old and fragile and weak, the black color of his hair replaced by grey. Coughing, fighting for every breath. They both knew what was coming, yet it was terrible for Magnus to just kneel next to him, to watch him passing away. To see the life leaving his blue eyes, slowly.
He remembered the moment Alec suddenly clutched his hand tighter, and he tensed immediately, looking at his face. He remembered the way he sais "I love you" for the last time, those being his final words. Magnus said it back, pressing a kiss onto his forehead.
And then the grip on his hand loosened, and Alec's eyes closed.
He remembered everything around him shattering, the world breaking into thousands of little pieces that could never be put back together. He let himself cry this day, the way he never did before, the sobs shaking his whole body violently for what seemed like hours.
(He was gone, gone and never coming back. And there was nothing he could do about it.)
(He was not ready to let him go, he would never be.)
Even now, after all these years, the pain of this loss still remained. Sometimes dull and in the back of his mind, and he was able to function normally. And sometimes, when Magnus would wake up alone, it all came back, rushing at him with double force.
He'd look at the photo of the two of them then, the one he put beside his bed, on the nightstand. He'd get up and open one of the drawers, taking one of Alec's old sweaters that he kept even though the smell faded years ago. And he'd lay back on the bed, pressing the cloth tightly to his chest, burying his face in it, letting the tears fill his eyes. Trying to at least imagine that Alec was still with him, that he was there.
Even now, after all these years, he still loved him way too much.
(And he was not sure if the feeling would ever be gone.

That's it. Reminder: reviews always make me extremely happy, so please, write something?