Ryan the third wrote:Which in turn can lead to all kinds of crazy in combination with a western guy who does not know how to deal with that, and then the situation escalates.

I think that's the key sentence. I've always thought that part of the problem must lie with the western male part of the couple, not just with the so-called PXJ. Without wanting to sound disrespectful to those guys, I think a lot of times it's a matter of attracting these PXJ in the first place. Although I can't base this on any empirical study, it seems to me that western guys somehow attract these insecure women like magnets. And apparently it's a mutual attraction. It's just that I never hear these kinds of stories from my Taiwanese friends and I don't get the impression that it's a widespread phenomenon in Taiwanese couples (of course there are many exceptions). Or maybe Taiwanese guys instinctively (or due to cultural conditioning) know better how to avoid or appease potential PXJ behavior.
It sounds like bad news for western guys, but my conclusion would be that a certain type of woman in Taiwan, probably one with low self esteem (maybe due to overly protective or strict parents), is more inclined to date westerners. And western guys, thinking and acting in typical western ways, are naturally less able to deal with PXJ and thus the situation easily escalates.
Also, I believe one reason for PXJ behavior, apart from insecurity on the part of the PXJ, is that certain expectations that the PXJ had (whether realistic or not, and I'm not talking about dick size, lol) are not met by the western guy, resulting in disillusionment and perhaps a loss of respect.