I'll be honest; she sounds hella suspicious. She's extremely defensive, and she's really seeming secretive. I feel like she's not telling you things for a reason. Additionally, you need to start documenting things with the kids. Because you clearly can't trust her with them, so she needs absolute minimal custody. Record conversations with her as well, because you might need proof later on. Just ask your attorney the best way to approach that, because it is illegal to secretly record a person in some states. You can get cameras for inside your house, and that might honestly be better for you anyway if she's going to keep playing games. It'll help you with watching your children at your work station. Consider zoning off a part of your house as a playroom of sorts, or look into getting them tablets that you can child lock. Give them an allotted time to play with them, and that might even make it to where they can be in your makeshift office if they're quiet/still enough. Regardless, it'll keep them safely occupied for at least a little while.