I think there are problems with the study that article is based on, as outlined here:
"The problem? That finding is the result of a grievous misunderstanding on Dolan’s part of how the American Time Use Survey works. The people conducting the survey didn’t ask married people how happy they were, shoo their spouses out of the room, and then ask again. Dolan had misinterpreted one of the categories in the survey, “spouse absent,” which refers to married people whose partner is no longer living in their household, as meaning the spouse stepped out of the room."
To be fair, the author of the original study still believes that married women are less happy, even after realizing this mistake, but others disagree and think the evidence does not point that way.