Why is remembering Tariq so important to Laila

Tariq is Laila's next door neighbor, a few years older than Laila. Tariq lost a leg during a war, and many of the people in the neighborhood refer to him as the cripple. Yet, Tariq has a strong heart, and he stands up for Laila when she gets picked on. Tariq and Laila fall in love and conceive a child, but then Tariq's family moves to Pakistan to avoid further violence in Kabul.