Have you ever hung out with a couple who is dating or engaged and they say, "We haven't even had our first fight yet!"
You know who else hasn't had their first fight yet? Strangers.
The reality of relationships is that we will hurt one another. We will have disagreements and fights. It's certainly not the goal of relationships, but if you reveal enough of yourself and learn enough about another person there will be pain and conflict.
Sometimes it's the result of trying to create space emotionally. We say or do hurtful things and we know which things to say or do because of how well we know each other.
Sometimes we respond to the examples we grew up with from our own family. We fight or nag when we should have a conversation because that's what we saw modeled.
Sometimes we take out frustrations from work or other relationships out on those who are closest to us. We feel stuck in other spaces and we take out aggression on the ones we love the most.
If we constantly move on from relationships when there has been pain or conflict we will end up in a world of strangers. While we shouldn't always reconcile because of abuse, we benefit greatly from dealing with the pain and finding a path forward in our relationships.