That statement was based on the various accounts of expat life in Asia that I'd read online, such as:

But as I often reminded myself, I hadn’t come to Asia for a boyfriend. I’d come because I wanted to master Japanese and explore a culture drastically different from my own. But I just hadn’t expected that moving my life to Japan would mean leaving my love life at home. As much as I’d enjoyed my life in Tokyo, it just didn’t seem like a fair trade. Not that the female dating situation in Japan wasn’t without the occasional success story. I knew of a few women who’d come to Japan and left with husbands or fiancées in tow. But they were the minority. Most western women came to Japan single and stayed that way.

http://www.vagabondish.com/female-foreign-japan/

When I’m in China, I tend to turn a lot of heads, especially in the countryside — and that’s not just because I’m a foreigner. It’s because I’m often seen holding hands with my Chinese husband. It’s true — the sight of a foreign woman and Chinese boyfriend or Chinese husband is much rarer than its counterpart, the foreign man and Chinese woman.

http://www.speakingofchina.com/china-articles/foreign-women-chinese-boyfriend-chinese-husband/#.UI1vlq5ZjxE

Between the tables of men sits a gweilo (Caucasian) woman, She is alone, reading the local expat English-medium magazine. She is wearing glasses and a shapely gray dress. She’s the kind of girl I would have set up with my brother when he was single. None of the men around her have glanced her way or made eye contact.

http://blog.expatsisterhood.com/2011/11/09/single-women-in-hong-kong-stream-of-consciousness/

Expat women face an unfortunate predicament in China and, from what I hear, throughout Asia. Their problem is that the expatriate men who come to China come for the local Chinese girls – and the local Chinese guys are too intimidated to go for expat women, or are too focused on finding a local wife, and in any event really aren’t all that attractive in their own right. What that means, of course, is that there are a lot of lonely expat girls in China.[...] It's something you can tell right away. When I first moved to Beijing, I saw three Russian women on the subway, one of them strikingly beautiful, and the other two not half bad. The instant I started talking to them, you could see their faces melt, and they just about started staring at me like a fat kid looks at a hamburger. I'm starting to think of this as the "expat girl stare" and I get it everywhere I go that there are expat girls. Even the most drop dead beautiful women here blow open to the lamest openers you can imagine, because they're so thrilled to meet a man who's actually interested and is the kind of guy they could get together with. Women of a caliber of looks I used to have to sometimes take a little while to crack open in California, or who might at times be downright cold to me on my approach, open easily here.

http://www.girlschase.com/content/dating-china#ixzz2AcNEouhM

"The majority of men come here because they have issues back home ... or they just can't get a woman back home for a number of reasons," she said. "They come here because they become a big fish in a little pond; they become very important and sought after."[..] For these reasons, these women see the pool of single, dateable foreign men more as a small puddle. And they don't consider dating locals a viable option.

http://www.chinadaily.com.cn/china/2006-11/11/content_730390.htm

I know three guys married to Chinese girls and one in a long term relationship. In more than six months in Shanghai I can recall seeing only one obvious couple where it was a Chinese (looking) guy and a Western girl. Some women understandably get bitter here. Stepping off the plane is like aging ten years and gaining twenty pounds.

That's been my experience in China - I can remember meeting only one instance of a western girl with a Chinese guy, but it seems that over half western guys had Chinese girlfriends. I don't know if expat men actually prefer dating local women, since the vast majority of girls there are local.

But then my experience has been slightly different, as I spent more time in student circles than in working expat circles.