It's "no need to fit in words that you would never say".
But anyways, as far as the meaning goes. It's obvious in the beginning - She starts fights with him for not showing her any love or affection, when it's because he's off cheating on her. And she thinks it's sad, that a perfect time in her life ended off with so many tears and grey days. And she's saying that he was a waste - never did anything, never will do anything.