For one-percenters like Tom Cruise and Katie Holmes, it’s easy to get the world’s fastest divorce. Their legal split took only two weeks. But for the poorest of Americans, divorce is still a luxury item.

So begins the Huffington Post’s coverage of new research out from Ohio State University researchers Dmitry Tumin and Zhenchao Qian, the gist of which is long-term separations are increasing. The authors report that, in their longitudinal study of over 7,000 people, about 85% of spouses who separated got divorced within 3 years, but about 15% hadn’t signed the papers within 10 years. HuffPo goes on:

…[R]esearchers said there was an economic reason… they simply could not afford to get divorced, especially when there were children involved. The study found that the married-but-indefinitely-separated group generally had only a high school education, were black or Hispanic, and had young children.

And the economic reasoning is both a push and a pull. There is the base cost of getting divorced, of course: ranging from just hundreds to thousands of dollars, depending on the complications of bringing in lawyers to take care of custody arrangements and joint property, it takes some cash to split up. But there are the financial benefits of staying married to consider, too: joint tax returns and shared health coverage are among those cited by HuffPo’s author Catherine New, along with the lower cost of shared rent or a mortgage, childcare costs that can be alleviated by swapping duties within the household, and so on.

New adds one final thought for those optimists who think it’s not the money—a separation might actually just be bringing those 15% closer again (the “absence makes the heart grow fonder” line of reasoning): the Ohio State study finds that 5% of separated couples did get back together. But half of those got divorced anyway.