Stefan knows it's not going to be easy, moving on from his one true love. But for the sake of everyone involved he knows he's got to try. She's not the girl he once knew and she's probably never going to be again either.

It's hard distancing yourself from something that once upon a time gave you the greatest joy in the world.
Sometimes he thinks it would have been best if he never would have introduced himself into her life but then again he wouldn't have had those great moments with her and he wouldn't have known how it would feel to love someone with everything you have and all that you are.

So, if losing her is the sacrifice he has to make to know what it feels like to truly and deeply love somebody, then he's not going to be sorry for loving her.
When he told Rebekah all those months ago to erase all of her memories from his mind, it was an act of desperation.
His heart has just been ripped out, stomped on and walked over all at once and he thought the best way to end all the pain and agony was to have it all go away.
He told Rebekah that while looking into Elena's eyes, the eyes that used to be full of love for him were now portraying hurt and sadness, but in that moment he could not care less.

In hindsight he's really glad Rebekah didn't compel all of his memories away because once he calmed down a little and thought about it, and he means really thought about it he would be so miserable without her memories.
He's pretty convinced that he would have felt like missing something for the rest of his life without knowing what it was he was actually missing.
And, if he's being totally honest and he can rationalize it pretty easily right now because it has been a couple of months, it wouldn't have been worth it.
In the end the good memories outweigh the bad and he wouldn't be the person he is today without their shared memories.
So, he's glad Rebekah chose not to grant him his wish and let him keep all of his memories because like he once said 'memories are too important'

He does sometimes wonder if it wouldn't be the best for Elena to have her memories of him erased from her mind.
He knows they had a lot of great moments together but he also brought her a lot of darkness, misery and doom.
If he never took the risk to get to know her then Damon wouldn't have felt the need to come into her life, she probably wouldn't have known about her adoptive parents (one of them being a vampire none the less) and Jenna, Alaric and Jeremy wouldn't have died.
But, if you really think about it, coming into her life was also a good thing. She is the doppelganger and Klaus would have come for her and she would have been introduced into the world of vampirism with or without the Salvatores.

Her adoptive mother Isobel once said 'As long as you have a Salvatore on each arm, you're doomed'
Stefan can't say he completely disagrees with her but he can't agree with her either. In the few years that he's known her Damon & him have saved her from death and destruction multiple times, something he's pretty sure she couldn't have done on her own.

When they were together she told him multiple times that her life already had bad stuff in it before he came along and that he should never feel guilty for loving her because she wasn't going to feel guilty about it either. But, like he told Caroline when she first turned into a vampire, he knows he should have walked away from her a long time ago but he just can't.

Elena is the kind of person that once you love her there's no easy way to shake her. She's so kind, compassionate and honest that she just imprints herself on your heart and once she's there she doesn't leave.
He still can't believe how quickly she got over the fact that he was a vampire and that she chose to love him despite of it all.
The moment she first uttered the words 'Stefan, I love you' she got a hold of his heart and she's had it ever since.

So, now it's hard for him to leave. He knows he said he would, and he plans to, trust him.
He just knows it's going to be hard. Everywhere he goes there's going to be a part of Elena he takes with him or a part of him that stays here with her.
Somehow it feels like they're tethered. He just feels this great magnetic pull towards her and every time he tries to take a step away from her that tether is there to pull him back and remind him that he can't just leave. He's dreading the day that he's going to have to tell her that he's leaving.
He doesn't know how she's going to react after everything she's been through and after all of the people she lost.

He's not sure she's quite ready to lose someone else, but that can't be a reason for him to stay.
He needs to get out of this triangle of hell and doom because it's tearing him down.
It's intoxicating his already unhealthy relationship with his brother.
He knows Damon loves Elena and he gets that, he does, he understands, because what's not to love. But it's a selfish love.
Damon couldn't let go of the Sire bond when he found out about it because he was too afraid of losing her and look what happened in the process.
She turned off her humanity; broke the sire bond, lost herself and because of that in the end lost her anyway.

Right now, she's not in love with anybody, she doesn't feel anything,or so she says. Stefan knows better than that. Having his humanity turned off not that long ago himself he knows there's a difference between not feeling anything or not wanting to feel anything. Sometimes, he just sees this tiny bit of shimmer in her eyes when he talks to her or something happens and he knows she remembers and maybe even feels something but as soon as it comes it goes.

He remembers Lexi once telling him that people need a reason to turn emotions back on and that love's the key to all of this.
Once you can hurt, you can love
But how do you make an emotionless vampire love anything or anyone for that matter?

He knows that when he flipped his switch that he didn't feel anything for a long time and when he tried to let it back in slowly it just hurt so freaking bad.
All of the thoughts and emotions he had suppressed during that time came rushing back in and he wasn't lying when he told Elena that if he let himself care all he felt was pain.
And, yes it was a slow hurtful process but in the end it was worth it. He can truly say that he loved better, greater and more after his whole Ripper Stefan faze and he never thought that was possible.

He just knows that Elena is going to need all the help and support she can get when she does turn back on her humanity but he can't be one of those people.
It would hurt too much. He knows that Caroline, Bonnie and Matt will all be there for her once she's back to herself, but he just can't be.
It has been too long, it hurts too much and he can't do it anymore.

He knows it's harsh and he understands it's selfish but just this once he's going to act on his selfishness and get the hell away from her life and Mystic Falls.
He has brought that girl practically nothing but trouble since the moment they laid eyes on each other and he's done. He has to be.
He can't keep doing this, not to her and not to himself.

But, how do you walk away from the one thing that brought you not only the worst heartache but also the best love ever?