Detour (1967)

On the road one day two people meet again after seventeen years. They'd had a brief, burning affair seventeen years earlier, in their idealistic youth. That had been just after the war, the time of great enthusiasms and faith in the future. Wishing to dedicate themselves to the new society they had chosen to renounced personal happiness, considering their love as an impermissible sidetrack from the requirements of the time.