What if we cannot agree on our child custody arrangement?

The court will decide for you. You should try to work it out. Negotiation is always better than imposition. If you leave it up to the court to decide, you are including the element of surprise. The judge will often appoint an attorney for the child and a psychological evaluator to make recommendations regarding custody and visitation. You can never tell what a judge may decide and you may discover that it is neither what you, your spouse, nor your child(ren) desire.