The love of God is so immense that he had to create. The physical universe is the physical manifestation of God s love and he could no more not create than we could choose not to eat or drink. For God, the real issue was not whether or not he would create but, rather, what form that creation would take. God had to make man. I will return to the example of a married couple.
Children complete a household filled with things.
Possessions are nice but they do not take the place of children. God, too, needed children to complete himself. God has angels but angels are servants. We humans, too, can have servants but servants are not children and we are not attached to servants as we are to our children. So it is with God.