They say two can live cheaper than one but I never believed this. In this CNBC article, there is discussion of the marriage penalty and how it can be expensive at tax time to be married for some:

Some wealthy and low-income married couples are losing out at tax time, but experts say eliminating the so-called marriage penalty is more complicated than you might think.

“It’s just impossible to get rid of it with the tax system that we’ve got,” said Roberton Williams, senior fellow at the Tax Policy Center think tank.

That’s because the U.S. tax system is progressive, meaning that people pay more taxes as their incomes go up, and also factors in whether people are married or single when it comes to filing taxes.

Williams suspects that more couples get a marriage bonus than a marriage penalty, meaning that their overall tax bill is lower because they are married. But he said there’s no question that some people would have a lower tax bill if they were single instead of married. ….

Some same-sex spouses will be getting a bonus or paying penalty for the first time this year, because this is the first tax season that the Internal Revenue Service is recognizing those unions. Cain said tax implications are not keeping same-sex couples she knows from getting married in states where it is legal.

“Most of the people I know say it’s the price of equality,” she said. “We get to get discriminated against in the tax system just like opposite sex couples.”

Notice that when “equality” means progressive politics and increased taxes, suddenly marriage is a good thing and no one stops to think about the incentives much. Really?