A perfect, Godly marriage consists of a man and a woman living as man and wife, freely without anything between them, producing as many children as they can.
That is ideal. That is the perfection.
Unfortunately, we are all fallen people living in a fallen world. Society makes it impossible for most to live up to this perfect ideal. Family planning is a necessity when you are living in a metropolitan capitalist society. It's not good how humans have to limit something as natural as the joining of man and wife, but it is a necessary evil. We need to face that reality.
The Catholic Church has always been against contraception because it doesn't conform to this ideal. But when we moved from an agrarian society to an industrial capitalist society, that ideal slipped away. Nobody followed the teachings of the Church anymore, and it got so bad that in the 1950's, the Church finally relented and allowed the rhythm method to limit family size, with the argument that it is more "natural". But it is like Moses issuing writs of divorce. It was only permitted because of the hardness of our hearts. "IN THE BEGINNING… GOD SAID BE FRUITFUL AND MULTIPLY".
We should be aware of the realities of life and society, and be understanding of that. Only as long as we never compromise what perfection is. Be lenient and understanding, and never stop telling people what God's vision is.