The stages of a relationship: what research says, and where you two are

The stages of a relationship are the phases couples tend to move through on the way from strangers to a shared life: attraction, getting to know each other, getting serious, committing, and then the long, ordinary work of keeping it good. Researchers’ models sketch a similar arc,^2,7 but there’s no single proven sequence, and real couples skip steps, repeat them or take very different paths.^1,2

When researchers traced how 113 people in premarital relationships grew more or less committed to marrying over time, they found two very different patterns. For some, commitment grew smoothly with few reversals. For others, it lurched, with sharp drops followed by sharp climbs. The up-and-down group reported more negative experiences, but the two groups didn’t differ in how much they loved their partners.¹

The order isn’t fixed either. Among Americans ages 18 to 44, more have lived with an unmarried partner (59%) than have ever been married (50%).⁸ Some couples move in and then marry, some marry first, and some never marry at all. Where marriages are arranged, the order can flip entirely: Robert Sternberg pointed out that partners may start with commitment and little else, and grow into love from there.⁹

So read the models below as maps, not schedules. They’re handy for naming where you are and what usually comes next, which is most of what you need from them.

There isn’t one official list. Several popular books each describe five stages, including Susan Campbell’s The Couple’s Journey (1980),³ couples therapist Linda Carroll’s Love Cycles (2014)⁴ and, for dating, John Gray’s Mars and Venus on a Date (1997).¹⁰

These lists come from relationship books rather than research studies, so treat them as useful stories, not science. The two long-term lists do share a recognizable shape: a rush at the start, a rough patch when differences surface, then a calmer commitment that both people choose.

If you’re in the rush right now, our guide to the honeymoon phase covers how long it tends to last and what comes after it.

Researchers have proposed stage models too, mostly as ways to describe and study relationships rather than as rules every couple follows. Three are worth knowing.

Knapp’s staircase. Mark Knapp’s model, first published in 1978,¹¹ has ten steps in two halves. Coming together: initiating, experimenting, intensifying, integrating and bonding. Coming apart: differentiating, circumscribing, stagnating, avoiding and terminating.¹² Textbooks that teach it point out that people don’t always go in order: you might skip a stage, repeat one or be in two at once.² Researchers have since built questionnaires to place relationships on it.¹¹

Levinger’s ABCDE. In 1980, George Levinger proposed a five-phase sequence for studying long-term relationships: attraction, building, continuation, deterioration and ending.⁷ A list that includes an ending isn’t predicting yours. It names what can happen, so you can notice a slide early.

Sternberg’s triangle. Robert Sternberg’s triangular theory of love (1986) isn’t a stage model, but it explains why love feels different over time. It splits love into intimacy (closeness and connection), passion (romance and physical attraction) and commitment (the decision to love someone, and to keep that love going). Passion alone is infatuation, intimacy plus passion is romantic love, intimacy plus commitment is companionate love, and all three together is what he called consummate love.⁹

He also gave each part its own timeline. Passion rises fast, peaks and then settles. Day-to-day closeness can fade from view even as the bond underneath grows. Commitment builds slowly, speeds up and then levels off.⁹

That fits at least one snapshot. When researchers compared 446 people who were casually dating, exclusively dating, engaged or married, commitment climbed from casual dating to marriage, while intimacy and passion were lowest among casual daters, higher among engaged couples and lower again among married ones. It compared different people, not the same couples over time.¹³

Each stage tends to bring its own feelings and one conversation that matters most before you move on. Here’s our own map of them, built for couples rather than researchers: six stages and one off-ramp.

Why those talks? A few findings sit behind them.

• Change is bumpy. Researchers first predicted that the move from casual to serious would be the most turbulent stretch. Some studies found that pattern and others didn’t, so the theory now treats transitions of all kinds, such as a new baby or an empty nest, as times when uncertainty and friction tend to rise.⁵ In one study of 136 people, destructive ways of arguing were most common in the in-between “defining” phase.¹⁴
• Decide, don’t slide. Researchers who study cohabitation argue that moving in builds inertia, so some couples stay together, or even marry, partly because it’s hard to undo rather than because they chose it.¹⁵
• Know why you’re moving in. In a 2019 Pew survey, most people living with a partner named love and companionship as major reasons, but 38% also cited finances, 37% convenience and 23% wanting to test the relationship.⁸ In a separate study of 120 cohabiting heterosexual couples, spending more time together and convenience were the top reasons. The more partners said they’d moved in to test the relationship, the more negative their communication and the lower their relationship quality.¹⁶ That doesn’t prove testing causes problems, but it’s a good reason to say your reasons out loud.
• Money fights tend to repeat. In a diary study of 100 married couples, money wasn’t the most frequent topic of conflict, but money arguments were more likely to keep coming back and stay unresolved than arguments about other things.¹⁷
• Preparing for marriage is linked to better marriages. In a large random survey across four US states, people who had taken part in premarital education reported more satisfaction and commitment and less conflict, and had lower odds of divorce. It’s a survey, so it can’t show the preparation caused the difference.¹⁸
• The long middle can sag. Across 165 samples, relationship satisfaction was lowest on average among couples about 10 years in, and higher among couples about 20 years in.¹⁹

Look at what you do, not how long it’s been. Stages show up in behavior: how you make plans, who you tell, and what you’ve already talked about.

• Spark: you plan dates one at a time and still think twice before texting twice.
• Getting serious: you’ve had the “what are we?” talk and met each other’s friends.
• Building a life: you share a lease, a calendar, a car or a dog.
• Committing: you talk in years, and you’ve covered the big stuff like kids, money and where to live.
• The long middle: routines run the show, and romance takes planning.
• Renewing: you’ve come through a hard patch or a big change and chose each other again.
• Drifting: you talk less, steer around certain topics, or live side by side more than together.

Stages can overlap, too. Textbook versions of Knapp’s model note that more than one stage can be happening at once,² so you might be building a life and drifting a little at the same time. That’s worth noticing while it’s still a little.

It’s common, and it’s workable. The key is to talk about the gap while it’s small, before one of you starts feeling stuck or rushed.

A big gap in commitment is worth taking seriously. In a national US study of 315 unmarried, different-sex couples, about a third had a large gap between how committed each partner was, and both partners in those couples reported lower relationship quality and more conflict than evenly matched couples did.⁶

Most gaps come in a few familiar shapes, and each needs a slightly different talk:

• Pace: you want the same things, but one of you wants them sooner. Agree on a rough timeline and a date to revisit it.
• One step: one of you is ready to move in or get engaged and the other isn’t yet. Ask what would need to be true for them to feel ready.
• The destination: one of you wants marriage or kids and the other isn’t sure they ever will. That’s a values question, not a timing one, so give it its own evening, and maybe a counselor.
• Attention: one of you is planning the future while the other is enjoying the present. Neither is wrong; just say which mode you’re in.

1. 1

   Name it without blame

   “I think we might want different things right now” lands better than “Why aren’t you ready?”

2. 2

   Separate the what from the when

   Ask whether it’s the step itself that gives them pause, or the timing. Each needs a different conversation.

3. 3

   Make the next step a decision

   Whether it’s moving in or getting engaged, choose it together on purpose instead of drifting into it.¹⁵

4. 4

   Set a check-in date

   Agree to come back to it in a month or three, so nobody has to bring it up cold.

5. 5

   Get outside help if you’re stuck

   If the same talk keeps going in circles, that’s a good time to bring in a couples counselor.

Some couples find the big questions easier on paper. The Couples Contract is a guided way to answer them together and keep what you agree on, and it isn’t legally binding, so it’s about understanding each other rather than paperwork.