To me the song is about a man at the start of a changed mind and learning his tragic flaw, that's he doesn't love her the way he did anymore, and that it's the "last time" he'll be someone else to be with her. He is too tired of hiding the lie and wants to tell her, the sacrifice is too heavy. Their relationship was based on both parties lying (I tried like you to do everything..) and the adult thing to do is to finally walk away ("I never walked away"). And the larger meanin he's learned that's echoed by the back-up chorous is that everything has to end at some point.
To me the song is about a man at the start of a changed mind and learning his tragic flaw, that's he doesn't love her the way he did anymore, and that it's the "last time" he'll be someone else to be with her. He is too tired of hiding the lie and wants to tell her, the sacrifice is too heavy. Their relationship was based on both parties lying (I tried like you to do everything..) and the adult thing to do is to finally walk away ("I never walked away"). And the larger meanin he's learned that's echoed by the back-up chorous is that everything has to end at some point.