LOL, not in SF. Lots of Asian/Caucasian couples in SF, and they go both directions.
Hell, I remember one time on the bus in San Jose I saw a couple that was a Caucasian man and an Asian (Chinese-American I think) woman sitting side by side reading... He was reading a book in Chinese, and she was reading in English. At one point, he turned to her and asked her a question in her language while pointing at a passage in the book, and she answered him, and a little while later she did the same with her book.