"The mistake that nearly every couple makes is really easy to recognize, but is often only noticed in retrospect," Maigen Thomas, relationship coach, tells Bustle. "We all tend to get in a groove in our relationships and reach a point where we can start 'relaxing' a little bit. That groove, if it goes without notice, becomes a rut." This is that point in the relationship where you're super content because you're comfortable. To be fair, there's nothing wrong with being comfortable. It's better than having to go through a rollercoaster of ups and down. But relationships need to be nurtured. In short, Thomas says, don't get lazy. "The solution is to tighten the feedback loop and open up the communication early," she says. "For instance, my partner and I check in every Friday. We verbally recommit to the relationship and talk openly about any things that need to be addressed from the week. It gives us an opportunity to speak frankly about things that might bother us, and removes the chance to let things fester." Keep communicating and keep finding ways to fall for each other over and over again every single day. You may think you're happy now, but who knows what your relationship will be like if you make it a point to really put a lot of effort into it everyday.

For many, being super close with each other's families is something to be really happy about. Not everyone can have that kind of closeness. But boundaries still need to be established and enforced. At the end of the day, relationship coach, Jenna Ponaman, CPC, tells Bustle, the way you handle your relationship should be between you and your partner. "Family will intrude and give their two cents out of love, but be careful just how much you allow them to dictate what goes on in your relationship," she says. "If it happens, just take a step back and have a conversation with your partner. They’re the ones directly involved."

"One mistake I've seen many people make is to bring up important topics by text," Raffi Bilek, LCSW-C, couples counselor and director of the Baltimore Therapy Center, tells Bustle. When you've been in a relationship for a while, it's easy to forget the "rules" and just stick with what you know. Even if you know hashing out problems via text isn't a great idea, you'll just do it anyway. "But texting is a very poor medium for carrying on important conversations about your relationship," Bilek says. "There is no tone of voice or inflection to help you understand a person's true feelings or intent, and all too often misinterpretations can lead to big fights." If you really have something important or sensitive to talk about, hold yourself back from sending a quick text. It's in your best interest to just wait for a time when you can do it face-to-face.

"Mis-attunements happen all the time even in healthy relationships," Brooke Bergman, M.A., dating and relationship coach, tells Bustle. According to her, there are a variety of ways that we "mis-attune" to each other. Basically, this happens at any time when you don't accurately perceive what your partner emotionally needs from you. For instance, if your partner's upset, you'll try to do the best you can to smother them with affection. But that may be the last thing they want. Maybe they just need space to be alone. While this can cause issues, Bergman says, what really matters is you know how to repair these mistakes and re-connect. "What is a relationship but each of us teaching the other over and over that we love them and how we like to be loved?" she says. "When you overcome your own need to be 'right', and your own personal feelings of hurt in any given moment, you can come towards your partner with open hands and an open heart."

As you probably know, money issues are one of the leading sources of tension between couples. "This pressure ultimately touches upon our most basic psychological needs and drive for survival, safety, and power," Caleb Backe, Health and Wellness Expert for Maple Holistics, tells Bustle. "Many partners are too afraid to bring up such a sensitive topic and end up harboring intensely spiteful feelings." But if your relationship is serious or getting there, you're going to have to discuss it at some point. The good news is, if you really are happy in your relationship, you've probably learned how to properly communicate with each other in order to get to that point. So talk it out. As Backe says, "Surprisingly, this issue can often be solved by simply sharing your feelings and expressing your concerns."

Adopting a "tit-for-tat" strategy is problematic in relationships and is a common mistake Marisa T. Cohen, Associate Professor of Psychology and relationship expert, sees a lot, even in the happiest of couples. Score keeping happens when each partner keeps track of what they put into the relationship. "I don't necessarily mean regarding tangible items (though those count as well), but if a person is keeping track of every time[they] added to the relationship and expects [their] partner to reciprocate at every step, this can create tension," she says. When you do this, you're not focusing on the health of your relationship. This tends to be more about you as an individual. "Couples who truly care about one another should invest in the relationship, giving it 110 percent, for the sake of the relationship itself, not because [they are] hoping for a return in the future," she says.

Avoiding conflict is one major mistake happy couples tend to make. It's not hard to see why. "People conflate 'we never fight' with 'we're the perfect couple,'" Stanizai says. "But they could be avoiding conflict and missing out on further connection simply because they can't tolerate the discomfort of it." According to her, this can work if both partners have similar conflict styles. "But if only one avoids and the other needs to resolve immediately, that can lead to more disagreements," she says. So don't be afraid of conflict in your relationship. It's been said time and time again, but fighting in healthy and productive ways can actually help bring you closer together.

Being a "happy couple" doesn't necessarily mean you have to be happy with each other every single day. Having a healthy and successful relationship means you're going to make mistakes and that's OK. Happy couples are happy because they recognize that relationships aren't perfect so they never stop putting in the effort to nurture it and make it grow.