"I don't live up to her" is a lyric in the song "ungrateful people" The meaning of this lyric is that although a person failed me, he did not fail her, expressing a kind of pain and unwillingness to be abandoned and disappointed in his feelings. This song expresses that the man loves a girl deeply and is willing to give everything for her, even his own life.
The lyrics contain fragments of why you let me down and let her down. The original love words have already become wind and sand. You changed a person to accompany you, and since then I have been wandering around the world with a wound.