Your complaint was that the series ended "after they got together".
My point is that the series did not end after they got together; we've spent nearly half the series following them after they got together. They have been together for so long in fact that people started complaining about how the series wasn't doing anything interesting any more.
Now sure, I agree with you that it would be nice to get a sequel that follows them in college or as newlyweds, but it just feels weird picking THIS series to be the example of a series that ends right after the ML and FL become an official couple.