On their first date, he asked her if she had any debt. Today, they're a DINK couple in the world's most expensive city.

• Ryan Tan and Corinne Chow are a DINK couple in Singapore.
• Despite stigmas, they say they don't feel pressured to have kids.
• As the cost of raising children rises, the appeal of becoming a DINK is gaining traction globally.

On their first date, one of the first things Ryan Tan asked his now-wife, Corinne Chow, was: "Do you have any debt?"

Chow told Business Insider she was shocked by the question, but that her answer was no. Four years later, the couple is building a life together in Singapore, which currently shares the top spot on the list of the world's most expensive cities.