Foreigners living outside of Pyongyang

I am currently in Dandong (a city in China bordering North Korea). I was at a North Korean restaurant here, and the waitress kept talking to a guy at the restaurant in Korean. Later I spoke to the guy, and he told me that he is Chinese but he used to live in Sinuiju (the city in North Korea which borders Dandong) and that he lived there for 15 years. I asked if his parents were businessmen and he said yes.

I am quite shocked. I thought all foreigners lived in Pyongyang (aside from some foreigners in Rason and consulates in Chongjin). I asked him if there are many Chinese in Sinuiju and he said "Yes". Very surprised to hear all of this and honestly unsure of how true it all is.

What other information is out there about foreigners living outside of Pyongyang? I'm very curious.