Case. The children grew up and left; the partners are alone and find they long lived for the kids, not for each other.
Model. For years the system ran on one shared process; when it ended, the absence of a “couple” loop was exposed.
What helped. They reassembled shared meanings and interests as a two; treated the new stage as a chance, not a void.
Lesson. A couple must exist beyond the parenting project — or its end reveals emptiness.
See High availability.