Dating. Marriage. The honeymoon phase. New parents. Empty-nesters. There are all sorts of labels for the different phases of a relationship that society has normalized. And while these widely accepted labels surely can’t accurately describe nuanced details of every relationship, they do reflect an over-arching truth to what partnership means. That is, change is normal, healthy, constant, and key for keeping us on our toes as a means to grow independently and together.

“I would be very concerned if a relationship at 10, 20, or 50 years was the same as when you first began,” says clinical counselor Karla Ivankovich, PhD. True, but that doesn’t make weathering these changes easy or comfortable by any stretch of the imagination. For instance, if you go from having a sexy, lustful beginning to more of a stable, companionate love, you might end up having less sex, which may lead you to worry that you’ve lost a crucial spark. Or, perhaps you’re a new empty-nester who just shifted from a house full of kids to a quieter, less busy one that lets you reacquaint with your spouse via one-on-one intimacy. That, too, can be daunting.

Learning how to flow with these phases of a relationship is part of any healthy union, says Alexandra Solomon, PhD, licensed clinical psychologist and author of Loving Bravely. “A big part of the work of loving and being loved is making peace with the inevitability of change,” she says. “I often hear couples say things like this in my therapy office: ‘This isn’t what I signed up for,’ or, ‘We didn’t used to do it this way,’ or ‘We aren’t the way we used to be.’ I spend a lot of time normalizing relationship change with couples.”

“A big part of the work of loving and being loved is making peace with the inevitability of change.” —psychologist Alexandra Solomon, PhD

So, let’s do just that: normalize the evolution of a single relationship. As you go through life with one partner, there are some common changes and phases of a relationship you’ll encounter, and each is just as important to acknowledge and understand as the last.

Learn about the 5 changes that happen over time amid phases of a relationship.

Change 1: infatuation to vulnerability

The beginning of the relationship is usually smooth sailing, given that—according to the research of biological anthropologist Helen Fisher, PhD—the early days of love are powered by testosterone and estrogen. “This stage of lust lasts a few weeks to a few months,” says Dr. Solomon. “Psychologically, there’s early idealization. You’re invested in your new partner seeing you in the best possible light. You also see them through rose-colored glasses.”

Of course, this doesn’t last forever, which brings us to the end of our first first phase of a relationship. “There’s always a fall from grace: The first disappointment. The first fight. The first time you see your partner stressed, afraid, or demoralized. Or the first time you let them see you this way,” says Dr. Solomon. At this point, many couples begin to experience a “love hangover,” wherein they “realize love is more than a physical attraction, and romance does not equate to real life,” Dr. Ivankovich says.

When this happens and you become vulnerable and start to experience conflict, keep tabs on red flags, like recurring conflicts, difficulty opening up, and feeling hopeless about the relationship. In cases like these, Dr. Solomon suggests considering couples therapy to address issues directly and decide whether there’s a viable future for the union.

Change 2: vulnerability to stability

Vulnerability may prompt disagreements and real discussions about the future, but after the dust settles, there’s often a period of stability. “You’re figuring out how to work together,” says Dr. Ivankovich. “Partners stop trying to change one another and instead celebrate their differences.”

While the relationship is becoming stronger and more accepting, it’s common for desire to taper off. “If the early chapters were about round-the-clock time together, it is normal to begin to need a bit more space and time apart,” says Dr. Solomon, adding that this applies to intimacy as well. “In well-established sexually monogamous relationships, women especially tend to experience a decrease in spontaneous desire and an increase in responsive desire.” This means they’re less likely to want to jump their partner’s bones, but are often able to get in the mood with some encouragement.

But, she adds that the change into stability is easy to interpret negatively. “We are at risk of adding a story to the shift, like, ‘My sexual desire for my partner is changing, so it must mean we aren’t right for each other or I’m falling out of love with them,’” Dr. Solomon says, quickly clarifying that sexual desire is something to actively cultivate and work on in any long-term intimate relationship. “Sexual monogamy is far from boring when both partners are committed to continuing to evolve and explore their sexuality, as individuals and as a couple.”

Change 3: stability to commitment

Sometimes, the commitment phase of a relationship involves marriage or moving in together. Other times, it’s just a concerted effort to merge lives and stick together for the long haul. “This stage isn’t without its arguments, but you know that an argument is not the end of a relationship,” says Dr. Ivankovich.

This is also the period wherein couples begin to understand that sustaining a relationship takes work and a willingness to accept change and evolve in the same direction.

Change 4: commitment to attachment

“Long-term relationships move into attachment, which is about creating a home, protecting each other, safety and security, raising a family, and shared interests and values,” says Dr. Solomon. During this phase, you might choose a place to settle down, have kids, and invest in building a life together.

And although it’s not a necessary step or one that’s right for every couple, Dr. Solomon says having a child “alters how couples mark the passage of time.” The anchor your relationship is frequently the age and stage of your children: “Raising a child together brings new opportunities for connection around the shared purpose of family life,” she says. “Commitment deepens, and there are new opportunities for intimacy and closeness. There are also new opportunities for conflict.”

Each partner is making sense of how to be both an intimate partner and a parent—roles that are often in conflict with each other. And since you can’t go home again, as they say, returning to the situation of life with just your partner won’t look exactly as it did so many years ago. Yet, as previously mentioned, change is good. “When a couple has devoted decades to raising children together, the empty nest can be both exciting and a bit daunting. There is more space to nurture intimate connection, but it can take some time to settle into this new chapter.”

Change 5: attachment to “bliss”

The phase after raising children, or after putting all the pieces of your life into place, can often be the most rewarding. Dr. Ivankovich calls it “relational bliss,” because you’ve put in the work to nourish a love that’s equipped to stand the test of time. “In this stage, the couple recognizes what it means to love one another at all stages and continues to choose to do so.”

When couples embrace inevitable relationship changes rather than fear them, they get to discover new, exciting aspects of their partner that keeps the partnership constantly fascinating, Dr. Solomon says, adding that the same applies to sexuality. “Who you are sexually at 19 is different from 39, and 59. In that sense, a couple never makes the same love twice. The safety of the intimate partnership creates the conditions for adventure and risk-taking.”

All aspects of romantic relationships are constantly in flux and evolving, just like all human beings are. Sure, this can be challenging—but aren’t most things worthy of hard work and dedication? The answer is a whole-hearted yes, and the opportunity to grow both independently and within the scope your relationship is just a wonderful reality, not something to fight against.

Now that you’re clearer on how to embrace the phases of a relationship, a couple things you might not want to embrace: cheaters and narcissists.