Longterm relationships? Ron and Lavender lasted, what? Five months? Harry and Ginny didn't even get to the month and I think we all agree that Harry/Cho didn't even happen. It's true that JKR hasn't been keen on making her characters mess arround, which is kind of a shame, but it's not like her books are a call to chastity, are they?
Great chapter, by the way! Sam, you're the best fan-fiction writer ever!