I don't think it's the romance that happened, but the romance that didn't. Rowling turned me from a Harry/Ginny shipper pre book 4 to an anti-shipper. Book 5 just...stopped describing Ginny as a person, and started describing second hand accounts of the amazing things she did instead. And this is a couple Harry was actually there for. None of the couples actually seem like they like each other because Harry's so busy with his stuff he only takes notice when people fight, which is understandable, but it makes the random "romance" scattered about mostly feels negative instead of positive.