I dont get it.

I just don't see how people just walk away.
I don't get how they just give up.
I understand that every situation is different... but to just let go of something so important to you without even looking back..
How?
How do you do that?
Right now I wish part of me could just walk away from the hurt, but somehow I just can't do that.
I value the relationships I hold, because to many times have I had to wake up and not have them there.
How can you walk away from this, that easy.?
It is a burning feeling inside me, that is consistently there.
That no matter how much I care.. no matter how much it meant to me.. no matter how much I fight. No matter how much I don't sleep because it's all I can think about.. you don't care enough to even look back.
And that right there is what hurts.