Many couples reach a discouraging conclusion after years of unresolved conflict: “We’ve talked about this so many times—and nothing ever changes.”

When conflict becomes repetitive, it can feel pointless to keep trying. Hope fades. Conversations feel scripted. Both partners know exactly how the argument will end before it even begins. This is the nature of recurring conflict in marriage for many couples.

But stuck conflict doesn’t mean nothing can change. It usually means something important has...