The question of whether someone has marriage potential is, understandably, a deeply subjective one. However, most research and clinicians will highlight a few character-based qualities that are necessary in both partners to make a union work.

These qualities aren’t based on personal preferences. Rather, they determine whether the two individuals have what it takes to accommodate, as well as celebrate, your relationship through thick and thin.

For instance, a reasonable level of emotional maturity and capacity to make room for difference is essential across the board.

If you’ve been wondering whether your relationship has what it takes to last a lifetime, here are three signs that your partner could truly be your ride-or-die for life.

1. They Believe In Your Wildest Ideas

Whenever your faith in yourself dwindles, your partner steps up to help you revive it. You mention wanting to write a book or starting a café, and they immediately jump in to ask you what you want to write about or what you would like to name your cafe.

In other words, they do everything they can in their power to take you closer to your “ideal self.” If this sounds like your partner, then you’re in the opportune position of experiencing what’s referred to as the “Michelangelo phenomenon.”

The Michelangelo phenomenon is a congenial pattern of interdependence in which close partners “sculpt” one another in a way that brings each partner closer to their ideal self.

Research published in the Journal of Personality suggests that this phenomenon is driven by the mechanism of behavioral confirmation, which means an individual’s expectations about their partner can become reality, through behaviors that conform to their expectations.

In other words, what you believe about someone can influence how they actually behave, because your behavior shapes their responses.

There are three steps to this process:

• Partner perceptual affirmation. If your partner believes in the “best version” of you, your ideal self, they see you as who you want to become.

• Partner behavioral affirmation. Their behavior supports and encourages the traits you want to develop.

• Movement towards the ideal self. You become closer to your ideal self as the first two steps play out.

Researchers found that couples with higher behavioral affirmation have greater relationship satisfaction, in addition to better personal well-being, as their life satisfaction and self-esteem rise. Moreover, their loneliness diminishes and they show less indications of breaking up.

Let’s say that you’ve always envisioned becoming a writer. You’ve written poems and essays occasionally, and submitted them to magazines. A partner who affirms your identity and behavior would know about this, and engage with your work.

When they encourage you and discuss your ideas, seek out writing opportunities and celebrate your progress, they’re creating situations where your identity as a writer naturally flourishes.

The more they believe in your talent and treat you like a writer, the more you start behaving like one, which only takes you closer to your dream of seeing your name on the cover of a book.

The Michelangelo phenomenon is not only the key to a happier and healthier relationship, but also an important step toward becoming the best version of yourself.

2. They Defend You Even When You’re Not Around

Loyalty and trust are the bedrock on which every other relationship virtue stands. And in secure relationships, this foundation is permanent and guaranteed, regardless of your immediate presence or absence.

It could be at family gatherings or among friends, but if your partner always has your back and stands up for you without you even knowing, it’s a strong sign that their love for you isn’t performative or tokenistic.

Research published in the Handbook of Interpersonal Commitment and Relationship Stability explains that there are three types of commitment in relationships:

• Personal commitment. A person may want to continue a relationship to the extent that he or she is attracted to his or her partner.

• Moral commitment. They feel morally obligated to continue a relationship, whether they really want to or not.

• Structural commitment. They find leaving the relationship difficult because of external constraints or barriers.

If your partner defends you even when you’re not around, it could be a sign of personal commitment. They have nothing to gain from it, but they stand up for you anyway. It’s a clear sign of deep love and care for you. It could also be a positive sign of their moral commitment, that is, they value you deeply, so they naturally want to protect your image and well-being.

3. They Make Sacrifices Without Spotlighting Them

In any relationship, collaboration comes at the cost of making some personal sacrifices, since both partners have their own set of goals to attain. If they never keep a score on the number of things they do for you, it’s likely that they do not resent you for the compromises they had to make.

These sacrifices may be minute. For instance, you ask them to turn the light in the living room off when they’re in bed next to you, half-asleep. Yet instead of complaining, they get up to do it.

A 2017 study published in Social and Personality Psychology Compass highlights commitment and self-control among factors that motivate sacrifices in relationships. It also suggests that in highly communal relationships, people often make small sacrifices automatically, even when acting impulsively.

In other words, when partners are naturally caring and responsive to each other’s needs without expecting something back, they may be more inclined to make small sacrifices instinctively. For example, they may grab the last slice of pizza, but they do not hold back from offering it to you.

Finding the right person to spend your life with is never an easy decision, but certain traits can help you determine if you’re in the right relationship. No relationship is perfect, but if you notice your partner working on themselves and striving to be a better partner, it may indicate that they’re growth-oriented and willing to make changes for the sake of the relationship.

Of course, remembering to put in as much effort as you expect in return should be a given. To keep a relationship healthy and well-functioning, you need to consistently work together and appreciate each other for the things that strengthen your bond.

Is your relationship showing signs of marriage potential? Take this science-backed test to find out: Relationship Satisfaction Scale

A similar version of this article can also be found on Forbes.com, here.