This is just an idea that popped into my head.

I found your picture in my wallet
Still got your sweater in my closet
I'll bring 'em by, maybe tonight

It was one of the worst days of Sirius Black's life. How could she have done this to him. He loved her. He told her many times. Inside him was this horrible pain that he couldn't describe. It was a week ago but it still felt like yesterday.
And people asking how I'm doing
But every question still has you in
I say I'm fine
And I never think about you
But you're always on my mind
"Olivia, love" called Sirius "What time are we going to Hogsmeade?"

"I cant go with you today Sirius" Olivia sighed

"Why not" he whined playfully

"I have something important to do" she kissed his forehead.

"Is it for me
"The word doesn't revolve around you, you know" Olivia smiled

"yes but yours does" smirked Sirius as he tickled her.

They rolled around until his lips met hers. That was their relationship. Loving, warm, and mischievous.

I'm getting over you, whoa
I'm getting over you, most of the time
If I say it like I mean it
Then maybe I'll believe it
Like it's true
I'm getting over you
She cheated on him. He had seen her. Of course she denied it. Everyone denies it when they are confronted with it. When he confronted her, there was hurt in her eyes. He didn't know why though. She was the one who ripped out his freaking heart.
Been playing all the songs you hated
I called the girl I almost dated
She's not the one
But I'm having fun
And I'm better off without you
And I think it's what I want
He had started to resort to his old ways. He had snogged six girls today. But he still felt empty. That night after they had broken up he took a walk as padfoot. Then sitting by the lake, he broke down and cried. It took a lot to make Sirius black cry.
I'm getting over you, whoa
I'm getting over you, most of the time
If I say it like I mean it
Then maybe I'll believe it
Like it's true
I'm getting over you
Every time he saw her in the Great Hall, there was sadness in her eyes. Like he was the one who betrayed her.
Even if it takes forever
I'll get my shit together
I've been doing so much better
I'm getting over you
I'm getting over you

It was getting easier but not by much.
I'm getting over you, (I'm getting over you) whoa
I'm getting over you, most of the time
If I say it like I mean it
Then maybe I'll believe it
Like it's true
Sirius was watching Olivia from the hill. She looked happy. She was with a guy who Sirius thought was on the ravenclaw team. His arm was around her waist and hers around his shoulder. He said something and she laughed. Then she brushed his hair out of his eyes and kissed his forehead. Sirius couldn't believe it. She was cheating on him. He felt something in him die.
I'm getting over you, (I'm getting over you) whoa
I'm getting over you, most of the time
If I say it like I mean it
Then maybe I'll believe it
Like it's true
I'm getting over you
Sirius Black is empty and sad. Olivia hurt him. She tried to explain something but he wouldn't listen. Will he ever hear the truth.
I'm getting over you

She didn't cheat on him! I will add another part to this soon REVIEW