You know, there’s a fine line… I have tolerated it for far too long and now it’s time to get my dignity back. I don’t deserve to be treated like that, I’m better than that. And I need someone who’s better than you. It’s over.

At some point you will realize that you have done too much for someone, that the only next possible step to do is to stop. Leave them alone. Walk away. It's not like your giving up and it's not like you shouldn't try. It's just that you have to draw the line of determination from desperation. What truly yours will eventually be yours and what is not, no matter how hard you try, will never be.