So I was thinking about Izzy and Stede's duel lately and what I think most interesting about it is that though killing Stede isn't "on the cards" and Ed really deeply emotionally cares for Stede at this point even if not perhaps romantically, he still allows Izzy to carry on the duel.
And by allows I really mean that like, yes he told Izzy that they weren't doing it and Izzy said: "no you're not doing it, so I must." I really do believe that Ed had insisted or demanded that Izzy not do it, Izzy wouldn't have- though not without consequence. Because Ed is always always the one who has the power in that dynamic.
But he doesn't stop it. He turns away. He waits for Stede to get killed. Though why is this? I think it falls into the line of Ed being a very unreliable narrator, even to his own feelings and emotions. He plays a good game of not caring (because by and large he needs to), but he feels deeply, and I think is deeply afraid even here. Because if he confronts Izzy, if he makes Izzy stop, if he forces it then he risks breaking that relationship-- one of his oldest. And though Ed and Izzy have their issues, they're still bound together. Siding with Stede means that he's siding against Izzy. And then what? If he breaks with Izzy he has Stede left and though Stede says he's Ed's friend, that's a hard thing to trust. (and when he believed it, when he allowed himself to trust fall, all he hit was an empty pier. There is really no one for him at the end).
However, letting Izzy win or lose on his own merit, even if Ed loses Stede (which even Ed in some small part feels like it's a better thing to do- a better thing to let go of) that means that he can lose Stede without guilt. That he can let him go without guilt. And, if by some strange twist of fate that Stede wins (which I don't think Ed believes) then the break with Izzy is Izzy's own fault. He named the stakes and he lost. And though he ends up breaking with Ed anyway (sort of, but not really) there's still the part Ed can say: You did this to yourself.
