I have recently stumbled at an app https://www.phonespyapps.com/mobistealth-review . It can track GPS location of device you put it in and show you all the messages that have been sent and received.
There was one guy, which was stocking my teenage daughter, so I could not help myself and started spying on her.
I found out many useful information and prevented them from meeting. Did I act badly? Because I think, it is a good way to control children. How do you copy with anxiety for your kids?