The five stages of a relationship are the Merge, Doubt and Denial, Disillusionment, the Decision, and Wholehearted Love. Every single relationship moves through these five stages—though not only once.

Think of these stages not as steppingstones to a final outcome but rather as a series of seasons that we move through in an eternal cycle.

Here, the five stages of every relationship and how to navigate each one.

We often think all intimate relationships reliably progress from the initial meet-cute to giddy infatuation, to a series of small trials and tribulations, and finally to a blissful state of happily-ever-after.

It's a satisfying narrative we see all the time in the movies, TV, and music. In reality, love is a journey without a final destination.

We shouldn't expect that at some point in our relationship, we'll look back at the obstacles we overcame and say, "Well, that's it! We're here! We made it!" Because beyond wherever you are now, another hurdle awaits.

In other words, the stages of a relationship are not linear but cyclical. Even people who reach the fifth and final stage of a relationship—Wholehearted Love—will eventually find themselves looping back to Stage 1 to start the process all over again. But they can always find their way back.

This Love Cycles model is drawn from my experience as a couples therapist for the last three decades, studying couples at all stages of a relationship and identifying common patterns.

Here's everything you need to know about the five stages of a relationship and what skills couples need to weather each stage.

Enjoy this stage to the fullest—this is the stuff that makes dating so delightful and intriguing. At the same time, be aware of your heightened emotions. Take time to step back and observe your emotions and your relationship, and actively question whether this person really is the best match for you.

Get candid advice from friends who can make sure you're not missing any truly worrisome red flags while under this biochemical love potion.

Go slow with making any big decisions, too—the Merge can fog your vision and make you want to dive into situations that might not actually be wise or healthy for you in the long run.

In general, don't make decisions because you're "so in love"—because that's a temporary feeling of infatuation that will eventually fade.

RELATED: Honeymoon Phase: How Long It Lasts + How To Bring It Back

The second stage of a relationship is Doubt and Denial, in which we finally start to actually notice the differences between us and our partners. We wake up from the trance of infatuation with a thump, finding that the same qualities that once seemed so perfect have begun to annoy us. (His reliability now feels rigid; her generosity seems irresponsible; their adventurous nature feels like unnecessary risk.)

And unfortunately, friction is natural once we run up against each other's differences. Power struggles increase, and we marvel at the change in our partner. Feelings of love mix with alienation and irritation. Perhaps we're not "perfect" for each other after all.

As our disappointment escalates, so do our biological responses to stress. Depending on our personality and circumstances, we may want to fight or to withdraw.

For example, you may feel the need to fight to defend your values, which may actually translate into the desire to have everything your own way. It makes little sense to expect another person to be just like we are, and yet, at some level, many of us do tend to ask, "Why aren't you like me?"

At this point, the skills of conflict management are essential. Learn how to deescalate conflicts and face relationship problems head-on while treating each other with care and respect.

Remember that power struggles and arguments are normal parts of a relationship; they're not necessarily a sign that love is ending or that the relationship isn't working.

You'll need to learn to identify the difference between healthy disagreement and unhealthy control issues; the former can be worked through, while the latter may be a sign you should break up.

Because this is the stage where you're starting to recognize your differences, this second stage of a relationship is also a good time to learn your love languages. There are five love languages, and it's important for each person to know how their partner wants to receive love.

RELATED: Why Differentiation Is The Key To Healthy Relationships

The third stage of a relationship is the Disillusionment stage. This is the winter season of love, one that may feel like the end of the road for some couples. At this point, the power struggles in the relationship have come fully to the surface; the issues the couple have consistently shoved under the rug are now glaringly obvious.

Some people become perpetually vigilant, ready to fly into battle at the slightest provocation. Other couples might quietly move apart over time, putting less and less energy into maintaining the relationship and investing more outside of it.

At this juncture, our original experience of passionate love is often a distant memory. The "I" reemerges, a state that feels a lot safer than our former blissful experience of "we." Nevertheless, some couples may not question their commitment; instead, they may see this as a strong message that things need to change.

Clear the air and create space. Stop pushing problems under the rug and avoiding issues; as tiring as the repetitive arguments may feel, pushing them under the rug just leaves a lumpy carpet with much to trip over.

There may be a lot of negative energy in the relationship at this stage. To offset this, practice showing affection even when upset. Can you feel angry and be aware that something isn't working that you need to talk about—but still go to dinner and a movie together?

During the Merge, the brain notices only the positive and avoids anything that challenges that view. In the Disillusionment stage, the brain is zeroing in on all the relationship's deficiencies.

The things that are going right are ignored; the things going wrong get all our attention. Try to offset that process with an intentional gratitude practice.

The fourth stage of a relationship is called the Decision because you're at a breaking point. Emotional breakdowns, leaving the house for hours to get away from each other after a fight, and self-protective behaviors are all commonplace. So, too, is indifference and remoteness.

You know you're here when you begin to seriously contemplate leaving and even make plans for exiting the relationship. You may feel ready for an enticing new beginning with a new person.

In this stage, we make a decision—whether that's to leave, to stay and do nothing despite how miserable we are, or to stay and actually work on fixing this relationship.

When I see couples at this stage, I always encourage them to consider taking a new path, which is to decide to do some work before making a choice about the relationship. Many times, couples feel they want out of the relationship, but when they learn the skills to communicate effectively, years of resentment or estrangement can fade away.

Doing the work involves understanding your own role in your relationship's deterioration and committing to real change. If we make this last choice, we can learn the lessons that will help us become the best people we can be as we give our relationship the chance to grow and deepen.

Even if couples do make the choice to part ways, they can often do so in a constructive way, wishing one another well and understanding their own part in what happened.

RELATED: The 7 Stages Of A Breakup: How To Get Through & Move On

The fifth stage of a relationship is Wholehearted Love—when our relationship is at its healthiest and most rewarding. It's love's summertime, when the fruits of a couple's labors are fully ripe and ready to be savored. Couples experience true individuation, self-discovery, and the acceptance of imperfection in both themselves and their partners, recognizing there is no such thing as a "perfect match."

There's hard work still involved in this fifth stage of a relationship, but the difference is that couples know how to listen well and lean into uncomfortable conversations without feeling threatened or attacking one another.

In this stage, couples also begin to play together again. They can laugh, relax, and deeply enjoy each other. They even can experience some of the thrilling passion, joys, and sex of the Merge as each person rediscovers themselves in ways that let them fall in love with each other all over again.

Nourish yourself. The Wholehearted Love stage is fueled by the qualities of two wholehearted people: generosity, humor, flexibility, resilience, good boundaries, self-care, and a life with meaning and purpose.

Couples are able to stay in this stage as long as they're able to continually sustain their own wholeness as individuals, so make self-care and self-growth continual goals.

Know that there will be new challenges waiting somewhere in the distance but that you can be well-equipped to deal with them when they come. In the meantime, relish the journey.

RELATED: 11 Signs Your Relationship Is Getting Healthier