Then it will be gone. Not ours to have. Not to be diminished. Not to be disregarded. Shared moments, fleeting as they are, if they are deeply intimate and treasured at the time, are precious in themselves.
Time is such a paradoxical phenomenon, anyway.
At best we are forever struggling to figure out how to not live in the past, neglect the past or be defined by the past. The future is a struggle, as well. How to plan for it and envision it without living in anticipation of it and missing the present. It is truly a dilemma, our relationships to time. Brain damage forces us to realize the past, live in the present and admit to the uncertainty of the future.