Married for 36 years, Susan and Carter Hunnicutt of Milwaukee have been separated for the past six. They’ve been more than amicable. Susan, a freelance writer, lives in half of the duplex home they own. Carter, a musician and former fire captain, sends her half of his monthly pension and keeps her on his low-cost health plan. “We’ve been able to be cooperative,” says Carter, 61. Still, he characterizes their current agreement as “transitory.” Seeing that Carter has a girlfriend and sensing the ground starting to shift, Susan, 63, worries about how a divorce might affect her finances. So what should they do?

Since 1990, the divorce rate among people 50 and older has doubled. These so-called gray divorces, which tend to happen when spouses are past their peak earning years, can be particularly troubling for women, says Susan Brown, a sociology professor at Bowling Green State University. Research she coauthored found that older women who divorce see their standard of living drop an average of 45 percent, compared to 21 percent for men their age.

Susan suspects that a divorce would put a crimp in her modest lifestyle—one reason she prefers the status quo. But suspecting isn’t the same as knowing. So the two of us sat down with Rhonda Noordyk, a certified divorce financial analyst and CEO of the Milwaukee-based Women’s Financial Wellness Center, to assess three possible paths.

1 Stay married. This is clearly a money-saving option, especially for Susan. The Hunnicutts’ taxes are likely lower because they file jointly rather than as married filing separately, as others in their spot might do. And Susan’s health insurance costs are low. Those tax filings and the credit card they share for household expenses are strong proof of their ability to work together, Noordyk says. But there are risks. One spouse could run up debts that the other could be partly responsible for. In a worst-case scenario, if one of them needs to go into a long-term care facility, the expense could be a drain on assets for both of them.

2 Get divorced. While a divorce will bring closure, it will change the financial landscape. Paying for her own health insurance could run Susan at least several hundred dollars a month until she qualifies for Medicare. Then there’s housing. If they sold the duplex in a divorce, Susan estimates that the cost of renting a new place would eat through her share of the proceeds in seven years. And Susan isn’t sure she’s emotionally ready for the change. “Part of my identity is still being married,” she says. Which is why Noordyk tees up …

3 Consider a postnup. A postnuptial agreement—just like a prenup, except it’s signed after a wedding, not before—is a legal document intended to outline the terms of a possible divorce before either spouse files. But it can also redefine an ongoing marriage to help avoid a divorce. In Susan’s case, Noordyk says, a postnup could reduce her financial risks by codifying the practices the couple has employed for the past half decade, such as paying for Carter’s housing with the money they earn by renting out half of their duplex. Postnups can be complicated, however, and laws governing them vary by state. To put one in place, it’s essential that each spouse has his or her own attorney, which can run the couple a few thousand dollars.

Susan’s plan is to get a postnup. In fact, Carter says, the two of them have already begun talking about it. Susan has also started to apply for full-time jobs. “I think my future self would say, It’s a good idea to formalize this in some way,” Susan says. “I think I will be in a place of power if I take the reins and take action.”