How do you know when relationships are really over?

Relationships have to be the most problematic, yet enjoyable thing we face. But when do you know it's really over? Is there a tell tell sign, is there a letter or a note or even a text?

I have been in and out of the same relationship for almost a year now. Like most, it started out perfect and dreamy. Then one day we just started fighting like an old married couple. I think we both know it's over, but we're holding on to something and neither of us know what. There's all sorts of signs that tell me it's over with, but why can't I accept that when I know too I am really over it.

Is it part of our nature as women to always want to fix things? Or is it that we know we've found comfort and going back to the single world is just so intimidating. I know only being 26 that the dating world is far different now then it's ever been, and the "competition" gets more and more plastic as the years go by. By the time the "new comers" are up and dating the big boys, they are already 30 grand in debt from their new boobs and noses.

So help me out, how did you know it was finally over with your loved one?