Warning! Spoilers ahead for Justice League #61!
Green Arrow and Black Canary have consistently been one of DC Comics' most recognizable power couples. These two heroes have had an on-again-off-again relationship for years and are generally considered a fan favorite couple by DC readers. But now the latest issue of Justice League has Black Canary finally admit what many readers have noticed already: that as couple Green Arrow and Black Canary just aren't meant to last forever.
Justice League #61 by Brian Michael Bendis, David Marquez, and Tamra Bonvillain follows the League after they transport themselves to another universe in order to confront the invading Supervillain Brutus from the previous issue. Unfortunately for the Justice League the team soon finds themselves separated and alone after landing in the parallel world, and so most of the issue is spent on the League trying to regroup with one another so they could confront Brutus as a team. So when Hawkgirl reunites with Black Canary the first thing she does is ask Dinah if she's still together with Ollie. Black Canary's candid response is one that many fans could already predict: that they'll be together until Ollie "does something stupid. Again."
Green Arrow and Black Canary have been together for quite some time in the comics but their relationship has never been perfect. In fact the two of them have broken up only to get back together again multiple times over the years. Usually this is because Oliver Queen has a tendency to be pigheaded and impulsive when it comes to romance, which then results in Dinah deciding to take a break from Green Arrow to keep her own life more on track. This throwaway line where Black Canary predicts she'll have to dump Ollie yet again is a nice meta joke about how their relationship has been written in the past while still acknowledging that the two of them are a very popular couple in the fandom.
Currently Green Arrow is already in the process of maturing as a person and has been acting like more of a genuine leader since the start of Bendis' Justice League, so it's possible that he might not do something stupid again like Black Canary predicts. But it's also true that the two of them having a relationship fallout is practically tradition at this point. And due to the nature of comic books and established continuity it's unlikely that Green Arrow and Black Canary will ever move on completely from one another, so for now readers will have to wait and see what inciting incident will cause their next relationship fumble.
Now that both Ollie and Dinah are both core members of the Justice League roster this could be an opportunity for DC Comics to develop their relationship even further and have the couple permanently settle down. Only time will tell however whether these two heroes will be able stay together in the future or if they'll default to the same relationship cycle that's defined Green Arrow and Black Canary's relationship for years.