Yang Guo and Xiao Longnu: Love Between a Former Student and His Former Teacher
In Return of the Condor Heroes, the romance happens between Yang Guo a rebellious child (probably nine or ten) who meets a beautiful teenage woman, probably four or five years older than he is namely Xiao Longnu (which makes Huang Xiao Ming's casting quite inappropriate considering he is ten years older than Liu Yifei while Andy Lau's makes a little more sense, which I am yet to see). The relationship started off pretty much as a master/student relationship but it was later blossoming into attraction, which was taboo at that time because of the Confucian principles.
For some time, Yang Guo learned martial artist under the person he called "aunt" for some reason, even if she was just a few years older than he was. The teacher/student relationship was one where Yang Guo learned martial arts in the Ancient Tomb until he became an adult. This was because Yang Guo run away from the Quanzhen Sect of Taoists. After Grandma Sun dies from an attack by the Quanzhen Sect, she asks Xiao Longnu take care of Yang Guo. This teacher/student relationship started off like any one but one day, as an adult, Yang Guo fell for her.
Confucian principles was against the student dating the teacher. Remember, he has already ceased to be her student and she is now his equal (more or less) at this point. He is no longer learning under hear but that time, Chinese society back then had crazy rules like gender biases towards females, you might also consider that they think the bond between teacher and student is eternal. But one cannot deny that the relationship was over. This caused some strans between Yang Guo, the martial arts community and his surviving relatives. This resulted to a series of arguments and trials. One of their greatest problems was with Xiao Longnu's cruel senior, Li Mochou.
Aside from the cruel witch Li Mochou, one can also think of the wicked martial arts teacher Gongsun Zhi from the Passionless Valley. Okay Xiao Longnu IS an adult so it's not pedophilia but he lusted after her because of her resemblance to somebody in the past. The lust persisted itself even after both Yang Guo and Xiao Longnu married that Chongyang Palace, believing themselves to be the reincarnation of a couple that could not be together. This of course, led to the death of Gongsun Zhi when he plunged into death with his estranged wife.
The situation complicates when Xiao Longnu is poisoned Also, Yang Guo had a lover named Guo Fu who ended up slicing Yang Guo's arm in a heated argument (she's got issues). The couple was separated for 16 years. Just when Yang Guo gave up hope, he met his wife again in the same place where they trained when they were younger. The love endured itself and after the war, they both were able to make up for their missing years of what would have been marital bliss. They both became celebrated heroes after the war with Mongolia.