I think the song is about knowing that your partner is perfect in every way you can imagine, yet for reasons you don't even understand yourself, you keep messing things up over and over. Because of this you have to let her go so she can be happy. (thought I'd let you go.) Then when he says "Wish I could find the words to say never again no, no never again," he means that he really wants to stop ruining things but he knows he'll screw up eventually. Never again is just wishful thinking.
I think the song is about knowing that your partner is perfect in every way you can imagine, yet for reasons you don't even understand yourself, you keep messing things up over and over. Because of this you have to let her go so she can be happy. (thought I'd let you go.) Then when he says "Wish I could find the words to say never again no, no never again," he means that he really wants to stop ruining things but he knows he'll screw up eventually. Never again is just wishful thinking.