Moving in together in your 40s: how long is long enough?

There’s no proven right number of months. What the research on living together points to is less about when and more about how. The concern researchers raise is couples drifting into one address because it’s easier, rather than making a clear, shared decision.2

And if you’re in your 40s, chances are you’ve done this before.

How common is moving in without marrying at this age?

Very. Pew followed a national panel of people born between 1980 and 1984. By 2023, when they were 38 to 43, 77% had lived with a romantic partner they weren’t married to, and 37% had done it with two or more people.1 Of those who cohabited, 67% went on to marry someone they’d lived with, and 28% hadn’t married at all.1

That’s today’s 40-somethings. Moving in together isn’t a radical step for this group. It’s the ordinary middle of a relationship.

How long do people usually date first?

Pew’s data doesn’t measure the dating period before a move, so there’s no reliable “average” to aim for. It does measure what comes after: the typical cohabiting relationship in this generation lasted 18 months before it ended in either marriage or a breakup.1 Some go much longer. 26% of those who had cohabited had at least one live-in relationship that lasted five years or more.1

Marriage isn’t always the destination, either. 30% of US singles surveyed in 2026 said they’d be open to a long-term committed relationship with no plan to marry.4

What’s “sliding versus deciding”?

It’s the idea, from researchers at the University of Denver, that living together can build inertia. Shared rent, a shared dog and shared furniture make breaking up harder, so some couples stay together, and even marry, who might not have if they’d been deciding at each step.2

A follow-up survey of 1,050 married people found that those who moved in before getting engaged reported slightly lower marital satisfaction and commitment, and more negative communication, than those who moved in after engagement or not at all before marriage. The differences were small.3 This is correlational, and it surveyed people married within the past decade, not specifically 45-year-olds with a past. It doesn’t show that moving in early causes problems. What it supports is the habit of making the move a decision rather than a default.

What should you talk about before you move in?

The research doesn’t hand out a checklist, but the sliding-versus-deciding idea suggests one test: could you both say why you’re doing this, and would the answer still hold if the lease ended tomorrow? Beyond that, the practical topics are the ones that tend to come up at this age anyway, like money, kids, space and how often you actually want company. How often should you see someone you’re dating in your 40s? is a good warm-up for the last one, and your non-negotiables before you get serious covers the rest.

Key takeaways

• 77% of people now in their early 40s have lived with an unmarried partner.1
• The typical live-in relationship in that group lasted 18 months before marriage or a split.1
• Living together before a clear commitment is linked with slightly worse marriages in one study, and the authors’ explanation is inertia, not the move itself.32
• No study gives a correct number of months. Deciding together is what the evidence backs.