There is two ways of Desciribing this phenomena, THe scholarly way and the simple way
I am studying to be an Economist :P, and I can tell you that in a lot of relationships, even when people are married, people are still trying to max out their ultiliy, whatever makes them most happiest. For this man, despite he has a gf, he is still constantly looking for an “upgrade”, some girl that he would like EVEN more than this one. If you think about it, once a man finds the perfect girl that fulfills him in every way, then they would probably stop with the hunt for a better girl and stay content. Of course, a perfect girl is impossible.
But wait! You may ask “But I know a lot of guys (maybe 1 out of 10,000) that are content with their girlfriend and don’t want to get somehow a better girl.” This is true because this person’s moral values and/or reputation as well as the uncertainty about dating someone else is possibly greater than a sexier, nicer, and happier girl.
Where also is this seen you may ask? An economist did a study about relationships in corporations. She condluded this: A couple gets married, and live for a couple of years. But in a typical mom stays at home family, the husband goes to the corporation he works at. Then he meets a girl there that is wealthier and may have more interests in common at work. And thus, once this man gets even a little fed up with his wife, then he goes with this new hottie at work and dates her and starts a relationship with her. And it keeps going until he can’t find a better woman. OR, unless he, (like the above paragraph) has values that makes dating the new girl lose part of his utility instead of gaining it.
As for the simple reasons:
He is either
A) One horny mofo, that just wants to date girls and wouldn’t mind trying to have one gf in Taiwan and the other in the U.S. (Seriously, it would be almost impossible for them to find out about each other)
B)He is really embarassed to be dating, maybe he is embarassed to be dating a foreigner, or an asain girl. (In the U.S, unfortuanetly there is still plenty of racism towards Asians)
Feel free to call me crazy by the way