When parents divorce or separate, child custody is often the most hotly contested issue. However, child custody does not have to be determined by a judge. If the parents can work out a custody agreement on their own, courts generally will make the agreements part of a larger divorce decree or order, or just make the agreements part of an official child custody order.
In fact, courts favor parents working out custody and co-parenting agreements on their own. This is due to the fact that it is generally understood that parents know what is best for their child better than the courts do, and that the parents will sacrifice their wants for the needs and wants of their child.