According to historical records, they have nothing to do with each other. Zhang Sanfeng is a real historical figure, Wu Tang Zongzu, the ancestor of Neiquan, Tai Chi, a martial arts master and Longxing calligraphy. Guo Xiang is a non-existent figure in history. She is just a character in Jin Yong's novels.
Zhang Sanfeng has only seen Guo Xiang twice in Jin Yong's novels, but he likes Guo Xiang and Guo Xiang likes Yang Guo. Guo Xiang's life is the end of the book Sculpture of the Gods and the beginning of the book Forever Reliance.
Extended data
A novel relationship
Parents: Guo Jing, Huang Rong.
Ancestor: Guo Sheng.
Grandparents: Guo Xiaotian and Ping Li.
Grandparents: Huang,,.
Brother/idol/admirer/sweetheart: Yang Guo.
Shi Sao: Little Dragon Girl
Sister: Guo Fu.
Twin's brother: Guo Polu.
Brother-in-law: Yeluzi
Friends: Lu Youjiao, Zhu Ziliu, Shaanxi Ghost Painting Cave, brother historian, colorless Zen master, earthly cook, Baicaoxian, sage Yin, etc. All over the world.
Friendly animal: leopard (because she drank leopard's milk when she was a child, the leopard didn't bite her and liked her very much)
Master: King Jinlun (forced to learn from the master)
Disciple: Miss Fengling.
Disciple: Kill the teacher, Gu Hongzi, etc.
Big disciples: Jing Xu, Jing Hui, Jingjia, Ji, Bei Jinyi, Zhou Zhiruo, etc.
References:
Baidu Encyclopedia-Guo Xiang