well actually first was Korra, got shot down when Mako kissed her. Then there was Eska, who Bolin found out he actually liked AFTER they parted. Then there was Ginger who didn't really like him in the first place and confused him with her Mover personality… So Opal would be a Bolin heartbreak 4.0. And that's not counting any flings he may have had prior to meeting Korra

And I thought the fans have to worry about Suyin.