This is a ridiculous law. Mothers whose husbands or baby daddies have left them during or just after pregnancy would have to stop nursing or express milk so the daddy’s new girlfriend could feed the infant, who would have to be carted around like a football. Children would have enormous burdens of remembering where their homework, reference books, uniforms and sports equipment is at all times. Courts could compel air flights for small children whose other parent got up and left the state.
Custody needs to remain case-by-case.
If you ever had to deal with the family court system in this capacity, I doubt you would continue to have the worldview about it that you do.