A newly married couple in the 1980s pose in front of the double happiness character.

Keeping an er nai, a concubine, or second wife, became a social phenomenon in big cities like Shenzhen, Guangzhou, Beijing and Shanghai. Many young women of low social status were willing to be kept by wealthy older men. Some even bore children with their sugar daddies.

"This not only jeopardized the legal rights of the women in the marriage. The rights of the er nai and their illegitimate children couldn't be realized either," says Chen Mingxia.

The Marriage Law was amended again to meet these new social changes. In 2003, a second amendment to the Marriage Law was issued. In it, cohabitation of a married person with any third party was prohibited. It stipulated that man and wife should be faithful to each other, and respect each other.

Nowadays, another remarkable phenomenon in Chinese relationships has emerged, namely shan hun or "lightning marriages". In this case, a couple gets married shortly after their first date.

Most of the couples who enter into such quick marriages are people born in the 1980s. Unlike their parents, this generation is coming of age in an era of exploding wealth and rising expectations for material success.

No specific figures are available for lightning marriages. However, it seems clear that quickie marriages risk a quickie divorce. The latest figures from the Ministry of Civil Affairs reveals that, in 2009, China had 2.48 million divorces, an 8.8 percent rise over 2008. Many were the result of lightning marriages.

"Most 1980s people are only children. They are self-centered and not tolerant in relationships," says Chen. "If they want something, they want it now, the same with their relationships. They are prone to get divorced quickly instead of taking time to improve themselves and become more tolerant."