<human>:  How can I make sure my ex husband doesn't get custody of my children?
<bot>: Hmm. I would recommend first and foremost to seek professional help, and seek advice from an experienced lawyer, as you likely have a case for some kind of custody arrangement. But if you really want to learn more about family law, perhaps you could review and try to understand the latest version of the Uniform Child Custody Jurisdiction and Enforcement Act (UCCJEA) as it relates to the US.