Well, yeah. When a relationship is new, the challenges will be about fitting yourselves together. In an established relationship, it's often changes in the environment or lifestyle that cause new friction.

One thing that my partner and I agreed on very early is that we don't want to keep re-having the same fight over and over. We might argue for 4 hours at a time, but by the end of it, we've usually identified at least one actionable step toward improvement. So the fights we have now are not the same as we had in the beginning. In literature, that's the difference between static and dynamic characters, whether they grow over time.