For me personally this song is about wanting someone you can't have whether it's due to rejection or other situations, and instead you find ways to include this person in your life even if you aren't in theirs. "The perfect wife, but perfect ain't quite right" line shows that no matter who it is, it isn't the person you want to have. Also, the lines "things I've had, things I want to have" mean to me that at one point this person was in your life but now they are just a memory you hold onto.
For me personally this song is about wanting someone you can't have whether it's due to rejection or other situations, and instead you find ways to include this person in your life even if you aren't in theirs. "The perfect wife, but perfect ain't quite right" line shows that no matter who it is, it isn't the person you want to have. Also, the lines "things I've had, things I want to have" mean to me that at one point this person was in your life but now they are just a memory you hold onto.