They're repeating history, meaning they'll also eventually be together. This is a fun ending for a couple who the author and us all have already known would be together at some point. It's not even slightly "open ended," it's just "mid-progress" and a fun call back to the series' start. This is a comedy series. Love this. Having said that I wouldn't mind a spin off to see how these two idiots navigate their own romantic chaos but I'm satisfied.