What would you say to a parent who is actively teaching their child to steal?
You might tell them that they are teaching their child selfishness and to trust in themselves rather than to trust God. All of that seems straightforward. So let me ask you. What are you teaching a child when you move in together before marriage? Well, to think of themselves instead of others. That personal convenience outweighs moral conviction. And that trusting in yourself rather than God is the better option. One day they will make their own decisions. Will they follow in your footsteps?