Communication fails quietly before relationships fail loudly.

Relationships rarely break at the visible moment. Long before that, small things stop being said, assumptions replace checking, and the two people gradually stop being accurately known to each other. The loud failure is the point at which an already-completed quiet one becomes undeniable.

Watch for the early signs rather than the late ones. Are there things you no longer bother to say, subjects that have gone off limits, guesses that have replaced conversations. Reopening one of those now is a small act. Later it becomes a large one, if it is available at all.