‘Two timelines with one balance sheet’: Why big age-gap marriages can make retirement planning even more complicated

At some point, they may find themselves at different life stages: one is ready to retire, while the other is still building their career. And, from a financial standpoint, that can get complicated.

“You’re not planning one retirement, you’re planning two timelines with one balance sheet,” Jon Ulin, a financial planner in Boca Raton, Fla., told MarketWatch.

Age-gap relationships make retirement much more complicated. Here’s what you need to know.

Health and health insurance

In about 7% of opposite-sex relationships — or 5.1 million couples — the man is at least 10 years or older, while in 2% of relationships (1.3 million couples) the woman is 10 or more years older, according to the U.S. Census Bureau.

And in almost a quarter (23%) of relationships, the man is four to nine years older. So the issue is more common than one might realize.

In age-gap relationships where one spouse is nearing retirement, the younger spouse may not want to retire. Even if both spouses want to retire at the same time, whether they can afford to is another matter.

And one of the biggest cost considerations is health. At 65, the older spouse is eligible for Medicare. But if the younger spouse is 55, they’ll need to bridge the gap for a decade.

The retiring spouse could see if their employer offers spousal coverage extensions, but extensions are typically 18 to 36 months — so it’s not a permanent solution (but helpful for couples who are retiring a year or so apart).

That likely means purchasing individual coverage through the Health Insurance Marketplace, which averages around $540 per member, per month, according to the Peterson-KFF Health System Tracker.

“The alternative is having the younger spouse work another 10 years, which often sounds better on a spreadsheet than it does across the kitchen table,” Ulin told MarketWatch.

At the same time, the older spouse is more likely to develop health issues — 93% of older Americans have at least one chronic disease, according to the CDC.

In these instances, the younger spouse may end up taking on more of a caregiver role. This could pull the younger spouse away from work, leading to accumulating losses in lifetime wages and benefits — including Social Security credits and pension plan accruals.

And not all health-related costs are covered by Medicare, from home modifications to long-term care (LTC) costs. In Milliman’s 2025 Long-Term Care Index, the consulting firm calculates that 65-year-olds should set aside, on average, $135,000 for future LTC needs.

Using up a chunk of your nest egg to pay for medical expenses means there’s less for the younger spouse when they retire — and if they, too, eventually need long-term care.

Retirement savings and Social Security

Even in cases where medical costs aren’t an issue — or at least not yet — the younger spouse may need to keep working to cover their day-to-day costs (which could build resentment). Or, the older spouse may need to start dipping into their shared retirement savings.

After all, just because one spouse retires doesn’t mean the couple’s household expenses suddenly drop. They still have to pay for housing, utilities, gas and groceries, as well as other expenses such as funding a grandchild’s college education.

These are the ‘go-go’ years, in which early retirees want to enjoy the fruits of their labor and spend money on bucket-list trips and big-ticket items — while they’re still healthy enough to enjoy them.

Dipping into shared retirement savings might help cover the shortfall, but that has long-term implications for the younger spouse. Couples with a significant age gap need to ensure their nest egg will last long enough to comfortably support the younger spouse in retirement, too.

Some age-gap retirees may claim Social Security early to avoid dipping into their retirement savings.