Every relationship and encounter is a learning experience. Through them, you can learn what kind of person you are compatible with, what person you aren't. You can also come to learn more about yourself, an aspect of relationships that is often unrecognized or underplayed. As important as it is when it comes to finding compatibility, it is also important to maintain a relationship once you establish one.
Being a good partner for the person you care about, even when the days get rough, is the most important aspect of relationships in my opinion. For me, this is being a healthy partner who can help the person I care about while also knowing when they need a little space or someone to talk to. This kind of feeling should not go away when you argue or disagree though, and this is often where some relationships can sour. The care and love you have for someone should not go away when you disagree. Being able to stick with the relationship no matter what is important in making sure the relationship doesn't die because of small spats.
Displaying good partnership and a good approach to the relationship can also help the other person. Often, we look to those close to us to guide us in our actions and approaches to different aspects of life. For some SO's, that may be how to apologize after a fight, or how to admit they feel overwhelmed by school or work. Show them your openness, your willingness to talk and apologize, or whatever good traits you can bring to the relationship. Your good example will help guide them in the areas they feel they fall short in.
Remembering not to idolize your partner or let your ego cloud your self-view both are fundamental to making sure a relationship is truly healthy and sustainable. Your partner will mess up sometimes, call them out on it and help them find a way to fix any damage done and move forward. But, you will mess up too, and that's okay. Often, we can be too stubborn to admit to our own errors or mistakes. By breaking the mold and allowing yourself to be flawed, but willing to learn and move on, you set the example for the kind of approach every relationship should take, especially with recurring arguments. If an argument happens over and over again, admit what the deep-seated issues are and come up with ways to improve and move on.
Relationships are not perfect or an exact science. All relationships require certain things to make them truly sustainable, healthy, and happy. The main one being communication, there are still ways to communicate with your SO beyond arguing, closing yourself off, or having to rant for an entire night. Practice honesty when you're upset and learn to be patient with both yourself and your SO. Two flawed halves do not make a completely perfect whole, but putting the effort of all kinds in shows how much your SO and what you have really means to the both of you