Compliments can certainly go a long way in making someone feel special and loved.

While you might think everyone loves a little flattery, one expert warns that some compliments may have unintended negative impacts on romantic relationships.

Psychologist Dr. Mark Travers explained in Psychology Today that sometimes what we say to thank our loved ones for their supportive behavior may be altering it.

“Compliments can be disarming. They make us feel chosen and understood in ways that other words rarely do,” the psychologist explained.

“But sometimes, the praise that feels the most flattering is also the praise that teaches us to edit ourselves.”

Over time, words intended to flatter someone can actually nudge a person to perform, conform, or shrink themselves to stay liked and continue to receive praise.

Consider the compliment: “How are you always so calm?”

If your partner grew up playing the peacekeeper in chaotic situations, this compliment might feel like overdue recognition. Yet, it can also come across as a reward for their silence.

“When emotional suppression is praised in adult relationships, it reinforces the message that your worth lies in being agreeable and low-maintenance,” Travers said.

This specific type of praise given to your partner could cause them to feel that they must remain calm — even when they’re not. They may feel encouraged to keep that mask on, even at the cost of their true feelings.

Another example is telling your partner: “You’re the only person I can talk to.”

This may sound like deep trust, but it could signal emotional dependency rather than intimacy.

People actually experience better mental health when they have multiple people they can turn to to process their emotional needs, each filling different roles—venting, calming or cheering.

“This diversity in emotional support leads to greater well-being, because no single relationship is overloaded with the task of holding it all,” Travers explained to the outlet.

While these two compliments should stay out of your relationship, there are a few key phrases Amy Morin, a psychotherapist and author of “13 Things Mentally Strong Couples Don’t Do, advises people to implement into their romantic vocabulary.

“If you and your partner regularly use these phrases, it’s a sign that you’re already a mentally strong couple,” Morin told CNBC Make It. “And if you don’t yet, you can start implementing them and find that you’ll grow stronger both individually and as a unit.”

Saying to your romantic partner, “I’m going to tell you something that may be upsetting to hear” is one of them.

“Acknowledging your mistakes and being honest about your needs can help you grow stronger together,” Morin said.

Another is, “I’m sorry for the part I’ve played in this.”

“When you take responsibility for your share, you increase the chances that your partner will accept responsibility for theirs, too,” Morin said. “Then you can both put your energy into developing a solution, rather than getting stuck pointing fingers and arguing about who caused the problem.”

Lastly, “Let’s find a solution” is another important sentence to say when your partner is struggling with something.

“While some problems are ultimately in your partner’s hands, like an issue they’re having with their boss, offering to work together shows that you’re invested in helping them make the best decision for themselves,” Morin explained.