Sorry for stating the obvious, but there’s a huge difference between spending 6 months in Taiwan and making a life here.
I’ve been in Taiwan uniterrupted for almost 10 years and I think it’s fair to say that I’m settled here, what with wife, kids, cars, house, job, and so on. However, Taiwan is not for everyone. There are things here that I love and there are things here that I (still) hate and will continue to hate until I die. I’m in a kind of a love-hate relationship with Taiwan and sometimes the relationship can be a bit stormy at best. I sometimes think back of my previous life in my home country – the space, the people, the air, nature … and I miss it terribly. Other times I remember the poverty, the crime, the hunger … and I regret not having left 20 years ago.
Last point, you mentioned your fiance lost some of the “sparkle” she had in Taiwan? Or maybe it was one of the other poster? Any way, make sure you don’t lose your “sparkle” once you are in Taiwan.
Ultimately, the decision is yours. Best of luck, mate.
Taiwan has been good to me.