In the background, Sakura is having a semi-serious love relationship with a fellow Japanese English teacher... and the only way that the writers could put them together is to have Thane breakup with Sakura (otherwise Sakura would look like a tart and her Japanese lover would be, at best, an oppurtunist).
Oh, and the reason Thane breaks up with Sakura? She's become "too Japanese". Nice cover... projecting upon the gaijin the Japanese attitude of "gaijin kusai".
