jealousy can be squared.
oo1. Hermione Granger
oo2. Ron Weasley
oo3. Lavender Brown
Hemione Granger and Ron Weasley have had an unspoken attraction to each other since .. well, it was noticeable during their Sophomore year, though some people have insisted that it had been since their Freshman year. Either way, neither will admit to it which makes the tension that much more noticeable. One would think that the bickering between the two would cease sometime, but each year, it succeeds in getting a tad bit worse. Ron has always been a little intimidated by Hermione's extensive knowledge and finds her need to picket and petition annoying. Hermione, on the other hand, dislikes Ron's "laid back behavior", in her opinion, and the fact that he's too daft to notice much of anything. And when she says much of anything, it usually means her. That would mean, she's a strong believer that the guy should be the first to admit what feelings he has or ... doesn't have.
Since the two were never a couple, and probably would never be, Hermione was the first of the two to take advantage of the whole summer fling ordeal. Not that she'd carried on a big, huge fling -- it was more just flirting and talking to an older guy over the summer. Of course, that caused more than a commotion when Ron found out who her new friend was. Viktor Krum. The guy that Ron had idolized for his football talent. Though, Ron's respond to the relationship wasn't exactly thought out perfectly. "Why on Earth would Viktor Krum like you?!" was what he asked. Hermione, offended with reason to be, ignored Ron for the rest of the summer. Why couldn't he just be happy for her? Viktor was the first, and only guy, who had shown some kind of interest in her besides wanting her to help with homework. Well, if Ron felt that way, Hermione could definitely ignore him graduation.
Of course, Ron refused to be outdone by Hermione; he knew she'd return to school and her little summer "friendship" would be the talk of nearly all the girls. Somewhere, deep down, he knew all eyes would be on him because of it. For that reason, he purposely searched for some girl to outlook and who was more popular than Hermione, which wouldn't be difficult, to pass off as his new girlfriend. It wouldn't be a fraud relationship; he'd actually date her, so obviously, he needed someone dateable. Most importantly, someone who didn't mind that fact that everyone thought he should be with Hermione. The closest girl that got to near perfect, or near tolerable in Ron's case, was Lavender Brown. She wasn't bad to look at, and even admitted to having a crush on Ron, BUT, she did express her dislike of Ron's friends. All of them, especially Hermione and Harry. Despite that, the two started dating a couple of weeks before school started and are still dating now. It's a miracle they haven't tried to kill each other yet.