Theon and Robb’s relationship is really open to interpretation in the books, but as a concept, imagine the tragedy of the miscommunication/misunderstanding where at the time Theon goes to Pyke, Robb is under the impression that in the past year they’ve gotten closer, while Theon is, on the opposite, under the impression that Robb has distanced/emotionally closed off from him and doesn’t really need him anymore.