Q. How do you know if you should fight?
A. You'll feel it deep down inside that they're the one.

Q. How long do you fight?
A. Guess that depends whether they're receptive or not.

Like Rhapsody said, fight if your life is better with them in it, as long as it's for the right reasons and you're not bullsh&**ing your self. (loneliness has a habit of clouding things)

You do what you gotta do, know matter how long it takes. I know, I'm going through a similar situation myself.