What if all devices are stolen

If devices that you purchased were stolen, you should contact the police. If you have another phone number (landline or friend's number) listed as a trusted number, you can get your authentication code on that device. If you didn't set up a trusted number, you may have to work with Apple to recover your account. See these articles:

If you think your Apple ID has been compromised - Apple Support

If you forgot your Apple ID password - Apple Support

Ask her nicely.

They wouldn't be stolen if your ex has valid purchase receipts for the devices. Otherwise, we are not attorneys and you should heed IdrisSeaBright's post.