It's a time-honoured tradition- every time Sam comes across Izzy (and Ed) in their travels, he asks Izzy to marry him. And every time, Izzy turns him down.
At this point, Sam is asking more for the sake of it than any belief Izzy will ever say yes, a remnant of childhood dedication touched with 30 years of heartbreak and regret- though even now, a small part of him still holds out hope. Sam's promises have only got more extravagant over the years, from a job as his first mate, to a captaincy, a fleet at his command, a whole fucking island if that's what Izzy wants- but he knows it isn't though, not really. If Izzy was ever going to agree to marry him, to leave his life and go with Sam, it wouldn't be for anything Sam could offer him. Izzy never did care for flashy shows of wealth, for a ship or to be captain. The only thing that ever mattered to him was loyalty given, and loyalty shown in return.
It all comes to a head after Stede left and came back, after Izzy lost a toe, lost his leg. Sam hasn't seen him since before things with Ed started to really slide off the rails, before stress permanently set into the lines of Izzy’s face. So, when he sees a dishevelled man with a hoof for a leg in a no-name port, he doesn't even consider the idea that he might know him. It's only when he turns towards him, and Sam catches a glance at those oh too familiar tattoos, he realises this is Izzy, his Izzy, that stands before him.
Knowing Izzy's discomfort with pity, he doesn't treat him any differently than he would in years gone by, positioning himself in Izzy's line of sight before approaching and sweeping him up into a bone crushing hug.
“Israel-goddamn-Hands!” he exclaims, as Izzy grumbles back a begrudging “Samuel-fucking-Bellamy”, a tradition almost as old as their friendship itself. Izzy might not hug him back, but he can’t keep the corner of his mouth from twitching, just for a second.
(If Sam holds Izzy a little tighter and a little longer than usual, well. That's his business)
By the time Sam lets go, most of the crew has appeared in the town square, drawn in by the commotion. They may have given Izzy his leg and welcomed him as one of them, but still there’s an underlying tension, with nobody quite ready to set aside everything that happened before the Kraken. Seeing him cosying up to an unknown man sets everyone on edge, unsure whether to come to their first mate’s aid, or to assume that they've been betrayed once again.
When Ed sees that the yelling was Sam, his hand goes tense where it's held in Stede's. He knows the routine, has seen it more times than he can count, but as he watches them part he realises that this is the first time in a long time he's unsure of what Izzy's response will be.
Knowing that something’s different, knowing that Izzy's feeling vulnerable already, Sam doesn't go for the same flashy proposal he’s been giving for years. He doesn't promise Izzy the world, he doesn't cause a scene (or, any more of a scene than he already has, anyway). He looks at the fractured man in front of him, takes his face in his hands, and says the exact same thing to him he said when they were little more than boys. “Israel, I have to ask you. I know what you'll say, but I have to try. Come with me. Marry me and sail away with me. I'll keep you safe”
And Izzy… hesitates. He glances over at Ed, at Stede, and says to Sam “...We’re staying in port for a week. Ask me again then”
That's the moment Sam knows there is something deeply, horribly, wrong. He's not just looking at an Izzy who got seriously injured in a fight and is struggling to cope, this is something so much bigger than that- and that Ed has something to do with it. Izzy wouldn't even be considering leaving if he didn't. Whether it was negligence or something more sinister, Sam doesn't yet know, but he intends to find out.
