Disclaimer: Unfortunately I don't own any of the characters.
Author's note: Okay I hope you like this, I've been feeling really emotional after 2x08 because Damon and Elena are becoming so intense! Anyway, feedback would be gratefully appreciated and enjoy!
He loved her more than anything and that's why he had to let her go. He had never felt this way about anyone before, and that was why he felt that tear roll down his cheek as he told Elena Gilbert he loved her and then removed that memory by compelling it away. He didn't and never would deserve her like Stefan did; Stefan would take care of her, Stefan would make sure no harm came to her and that she was always happy. Stefan would be the one to marry her and turn her into a vampire should she ever chose that path. Not him. He wasn't worthy of her.
"I love you, Elena."
He remembered looking into her eyes when he told her that, remembered that there were tears forming in her eyes, and that at any moment she would let them trickle down her face as she realised the solid truth: that maybe she was falling in love with Damon Salvatore and that she had been denying it the whole time; Stefan was a barrier to the love she was feeling for his elder brother, Stefan was the reason she couldn't allow herself to admit the truth; this was something Damon couldn't allow to happen. He couldn't put Elena through more pain than he already had. Elena deserved the best and he just wasn't that.
A pain so strong that made him feel like he was going to explode formed in his belly, and he realised it was because he had let go of the one thing in this world that he loved; that he lived for. He was letting go of the one thing that had repaired part of his humanity because he knew that the relationship he dreamed of having with her was impossible; she was in love with Stefan and he couldn't change that and he realised that he didn't want to either.
"It will always be Stefan."
He remembered that one day he had snapped for the worse, hearing those heartbreaking words and then snapping the love of his life's brother's neck, watching as he fell to the floor in a tangle of limbs, dead to the world and never coming back. He had watched the look of pure agony written on her face, as she crumbled to the floor next to her brother, begging him not to be dead, that she loved him and needed him. He had then watched as he brother excelled a breath and slightly opened eyes in shock and confusion and the look of relief that washed over Elena's face was heartbreaking for him; this was why he couldn't put Elena through that again.
She didn't deserve an unpredictable guy that when is angered and snaps, could easily hurt the people she loves the most; she didn't deserve a guy that had killed countless men and women in his years as a vampire; she didn't deserve to be constantly worried and not being able to live a life when she can't have fun all the time and is permanently worried what beast might come after her next.
Damon didn't think he could live with himself if he thought she would live pain for the rest of her life; he wanted her to be happy and if that meant sacrificing his love for her then so be it. He didn't think he would ever be able to get over her cute little smile when she was happy, the way she acted crazy when she was having fun – he smiled briefly, remembering the Georgia trip – and he didn't think he could ever get over how beautiful she was; she was Katherine's doppelganger yet in some strange way Elena looked slightly different and more beautiful than Katherine ever would or was. Damon pondered that this could be for the slight fact that Elena was everything Katherine wasn't; she was pure and innocent and put the ones she loved before herself. Katherine would never do this and would rather die than protect anyone. He thought Elena's innocence is what attracted him to her in the first place.
No one had ever cared about him in his lonely life, let alone apologized for the death of someone he might have loved.
"I'm sorry, about Katherine."
He replayed her telling him this and how shocked her words had been for him and then remembered how later that night when she had been fast asleep in her bed, looking as innocent as ever, he had slightly touched the side of her face. He had to admit that when he looked at her part of him still did see Katherine – she had been a big influence in his emotions for so long – yet he also saw the loving nature of someone and he thought that in that moment, he might have started to fall in love with someone that wasn't Katherine, but looked exactly like her.
But also, she wasn't Katherine.
He couldn't get this out of his head because on the outside they were physically the same, but on the inside they were mentally different and Damon knew this would never change. Elena's heart was filled with love for mostly everyone, whilst Katherine's heart was filled with ice that if touched would be broken into a million pieces, ready to snap at anyone that walked past her.
Damon Salvatore knew he would miss Elena. He knew his heart would always yearn for her; want to reach out to her heart as well; he felt that they could be twin flames – two halves of one soul - at least, he imagined that if he hadn't compelled Elena. He had seen that her love for him was about to become a lot stronger than it actually was and he couldn't allow that. He couldn't allow her to be a part of his eternity of misery.
She was free of him now to love and be with Stefan for the rest of her life. They would be happy together; Damon was sure of it and if they weren't, he would do everything in his power to make sure they were.
For the first time in his life, Damon was going to be selfless because that's what you did when you're in love – you sacrifice your own needs for those of your eternal soul mate.