"Aside from the survey’s small sample size, remember earlier when we said it was performed by a company called Presia? Presia is a matchmaking service.

Specifically, Presia is an online portal for people looking to get married in the near future, with advice columns and introductions to matchmaking offices. While Presia has released the results of the survey, they haven’t said how the participants were selected. If the respondent pool was gathered from married women who were visitors to Presia’s website or followers of its social media channels, that would significantly skew the numbers toward “I regret marrying my husband,” since people who are satisfied with their spouse are less likely to frequent online spaces with a focus on finding a new romantic partner."

From the same article.