Why did Virginia visit Sir Simon’s grave after her marriage?

As Virginia stepped forward and laid a large cross made of pink and white almond-blossoms on Sir Simon's grave, the moon came out from behind a cloud and flooded the churchyard with its silent silver. The nightingale struck up a note in a distant copse. Virginia thought of the ghost's description of the Garden of Death where a soul attains peace and beauty at last, and her eyes became dim with tears at that thought.