The plot for this series seems somewhat strange to me. Obviously, Zhang Ting is the female lead, who is in a cliched 'immortal falls for mortal' relationship with Roger. Because of this, the understandable audience response (especially for ZT fans I imagine) is for them to end up together. The 'strange' part is that writers gave the male lead a 'married background'. Attempting to be a light-hearted comedy, mixing in the issue of fidelity is not a good idea...especially if not handled well. Fidelity itself is a touchy and involved theme to play with, and obviously, Fairy Chalice is no Dr Zhivago.
Now, Liu Tao's role as the wife did no wrong. She was a good wife/mother. Just because her role was not the main and she wasn't Zhang Ting, doesn't mean she didn't deserve to end up with her own husband.
I sympathise with the relationship between Roger and Zhang Ting, but then, I personally thought it wrong. Call me a romantic at heart if you will, but if Roger truly loved his wife, nothing could intrude on that perfect harmony of Yin and Yang...there are only essentially 2 parts to the Yin and Yang, never a 3rd party. One can use excuses of memory loss, utter loneliness, 'moments' of weakness, yet the human mind/heart is very steadfast and strong if one wishes it to be. For Roger to love his wife truly, one thousand dazzlingly beautiful fairy Zhang Tings who showered him with undying devotion should not be able to sway him.
I'm sure if everyone put themselves in Xiu Xiu's shoes, they would think differently about 'cheering on' the Roger/Zhang Ting match.
And if that's the case, well, Xiu Xiu would probably be better off with Christopher Lee...he seemed to love her enough...at least based on this wonderful clip anyway...
http://you.video.sina.com.cn/b/709362-1252431135.html