Being single can make the search for “the one” feel impossible. Yet even after you meet someone you can picture a future with, a different challenge begins: keeping the relationship healthy as the years roll on.
Relationship therapist Andrew Marshall mapped out the typical phases many couples move through in his book I Love You But I’m Not in Love with You: Seven Steps to Saving Your Relationship.
Drawing on patterns he’s seen again and again, Marshall describes six major stages of romantic relationships—starting with the intense early rush, and stretching all the way to the long-term effort it takes to maintain closeness once life feels familiar.
Understanding these phases can help you make sense of how things are going. If you’re in completely different modes—one of you still merging into “us” while the other is ready to settle into routine—it can create friction fast.
Pinpointing where you are can offer perspective—whether your partnership is developing naturally or starting to lose momentum. Below is a reworked overview of the six stages, with the reminder that every couple moves through them at their own speed.
Stage one: The first year (blending)
Year one often feels like a whirlwind: attraction, novelty, and the thrill of discovering someone who seems to “get” you. It can pass quickly, but it sets the tone for everything that follows.
During this phase, many couples begin to fuse into a unit. The pull toward each other is so strong that differences can feel insignificant—or even charming. Oddly, that same intensity can make this a fragile period.
Falling hard can trigger fear, and some people instinctively hit the brakes. When that happens, tiny issues may suddenly look huge. The best approach is to keep perspective and avoid escalating minor conflicts into deal-breakers.
Stage two: Years two and three (nesting)
In the second year, the early high usually settles into something steadier. Instead of chasing constant excitement, you start working out what a shared life could practically look like.
As commitment becomes more real, pressure can build. You may both feel the need to let go of parts of your single-life identity, and that can bring nerves—or even a bout of cold feet—especially when the differences you brushed off early on become harder to ignore.
This is where communication matters most. Learning how to talk about small irritations without turning them into character attacks, and practicing compromise without resentment, helps the relationship strengthen instead of splinter.
Stage three: Years three and four (individual growth within “us”)
Once the day-to-day basics are smoother and your bond feels more established, many couples start asking bigger questions: Who are we together—and who am I on my own?
With smaller disagreements hopefully handled earlier, more substantial issues may surface. If you’ve already built healthy habits around problem-solving, these challenges often become another sign of progress rather than a breaking point.
A common struggle here is separating “we” from “I.” For someone with low self-esteem, it can be tempting to disappear into the couple identity instead of continuing to develop individually. Finding a balance—staying close while still staying yourself—becomes essential.
Stage four: The long stretch (collaboration)
After navigating those early hurdles, many partners enter a steadier stretch. You know each other’s quirks, you understand the triggers, and you’ve learned how to handle differences without constant drama.
This period often brings teamwork to the forefront—taking on shared goals, building a home life, pursuing a major project, or raising children. New joint challenges can be demanding, but they can also add freshness and meaning.
Even in a comfortable rhythm, risks remain. People don’t always grow in sync, and it’s easy for one person to surge ahead in some area. Protecting the relationship means investing in each other as deliberately as you invest in everything else you’re building.
Stage five: Around 12 years (the “fine wine” phase)
Reaching this point is a milestone. Ideally, the relationship is richer now—more layered, more secure, and more rewarding than it was in the early days.
Over time, you may repeatedly “re-meet” your partner as they change with life’s curveballs. But familiarity can also breed complacency, and couples sometimes slip into patterns where effort fades because the relationship feels guaranteed.
Staying close means refusing to coast. Prioritising genuine connection—attention, affection, and curiosity—helps prevent either partner from feeling taken for granted. For some couples, this renewed focus can even spark a sexual reset, especially when both people take time to listen to what the other wants, emotionally and physically.
Stage six: Around 25 years (the “rose garden” stage)
At 25 years in, the original spark has grown into something expansive and deeply rooted. You’ve likely learned most of what there is to learn about loving another person over decades, not days.
Still, no relationship is ever “finished.” One challenge that can creep in later is selective silence—choosing not to mention things that irritate you because they’ve always been there and you assume it’s not worth stirring up conflict.
Keeping conversation open doesn’t just prevent problems from stacking up—it can also refresh intimacy and keep you feeling connected as you continue building a life side by side.