Help finding fic
What I remember about this fic is that Arthur was a sort of guardian angel who was assigned to Eames, and he'd been assigned other humans before and had to watch them grow old and die and didn't want to get attached to Eames, but of course he did. And Eames frustrates Arthur because he's so prone to having to be rescued, and Eames has a wing kink and makes Arthur manifest angel wings during sex even though Arthur doesn't actually have wings.