Irving isn't giving us a conventional love story, so there isn't any romance to speak of. Yes, there's certainly a lot of courting going on as Ichabod Crane tries his level best to win the hand of the attractive heiress Katrina Van Tassel. But there's precious little in the way of actual romance, and with good reason, too.
As Irving is writing a humorous ghost story, a straightforward romance would kind of get in the way. Ichabod's courting of Katrina eventually leads to his frantic race with the Headless Horseman, so one could say that their burgeoning romance is really just the catalyst for the story's most significant and dramatic event.
Focusing too much on the romance element in the story would have made the transition to Ichabod's race with the Headless Horseman too jarring and rather clumsy. By downplaying the romantic element—as well as leavening it with a lot of humor—Irving makes the eventual transition to a ghost story a lot smoother.
In simple terms, then, the romance between Ichabod Crane and Katrina Van Tassel is just a means to an end. In other words, it's not the main focus of the story; it simply provides us with a way into the narrative.