About a hundred years ago, when a Catholic wanted to marry someone who was not Catholic, it was pretty standard that the non-catholic would convert in order for the marriage to happen. I have met numerous people who were in this situation. Sometimes the conversion was a bit "light". People have said to me, "I only became Catholic so that I could marry him" (or "her"). It was clear they understood the faith, but whether these "converts" were actually committed to the faith is another question.
For the Catholic, it helped them "dig in" and get more in touch with what it meant to be Catholic. And, because the spouse was a new Catholic, the spouse who was Catholic to begin with, would often seek to deepen his or her faith. This was a good scenario, and I would go so far as to say that it would do us well to restore it. In the rare instance where a Catholic was allowed to marry a protestant, it was common that the faithfulness of the Catholic helped the non-catholic to choose to convert.
Today, what happens when a Catholic wants to marry someone who is not Catholic? Usually, they get married, but there is no "push" for the non-catholic to convert. It is common that the non-catholic spouse never even is given the slightest idea that the Church wants them to convert. There is a reason that the Canonical term for a Catholic married to a baptized non-catholic is, "mixed marriage". It is mixing together two different perspectives, and although it can go well, it has extra challenges.
Sadly, there is another layer to the modern experience. That is the fact that a large percentage of Catholic/non-catholic marriages end up seeing the Catholic parties softening their faith, and many eventually just quit practicing the faith at all. The children are often not raised as Catholics, and thus their faith is damaged in the whole process. It used to happen on a rare occasion in the past; today it is almost commonplace.
How can this trend be overcome? We all need to deepen our faith, and seek to understand the Lord's answers to the world's moral and doctrinal compromises. If we solidify our faith, then it will be easier to help the next generation to solidify theirs. Yes, there will always be an occasional falling away, but it will not be because of the bad practices of certain weak Catholics, but in spite of them. If parents can be more diligent in handing on the faith to their children, and priests can be more dedicated to explaining the faith to their people, then we might see a change in the direction that our society is taking.