What is a word made up of 4 letters yet is also made up of 3. Although is written with 8 letters, and then with 4. Rarely consists of 6, and never is written with 5?
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 you're 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 is truly yours will eventually be yours, and what is not, no matter how hard you try, will never be.
Sometimes I pretend I'm trying to squash an ant but then I'll let him get away so he can run home and tell the story about how he made it out alive and get all the little ant bitches.