If she adapts to the Cambodian ways more or less completely, they may be fine for some time.But people can’t wipe out their cultural background that is more or less 180° diametrically opposed to the one they have chosen to live in. It shouldn’t be too surprising that the man expects the wife to bend to his way.
Traditions are very slow to change and the 30 years since the Khmer Rouge certainly weren’t long enough to whittle away at the most prevalent characteristics of the man -woman relationship.
The man knows it will be hard to adapt to Western culture, its different concepts and ideals, the way people do business, etc. If the Western woman is fine with living in Cambodia, as many Western men are with their Cambodian wives, there should be no initial problems.
The wedding ceremony in itself is a one-of-a-lifetime experience.
Now, I am no psychologist or sociologist so anything written her must be seen in this context. in their 50ies or 60ies, probably dating back to the Vietnam War era and its ramifications throughout the region at that time.
Especially in Cambodia itself, it is rather rare to find a mixed marriage between a Western woman and a Khmer man. The cases I have come across are always of the arranged nature, that is, U. Cambodians hire somebody to marry one of their kin back in Cambodia, thus enabling them to immigrate to the U. Although there were some crackdowns by Immigration and Customs Enforcement (ICE), according to my knowledge the practice goes on unabated.