oooeee jethro, I bet my H feels just like you.
You could ask her to call you every hour.
I wouldn't mind if my H asked me to do that.
I would like to be open about my ex-OM.
I mean, shining the light on the boogey man makes it hard for him to be sneaky.
I would suggest not being condescending.
Just state your fear as if it were scientific and ask (don't demand or tell) her to call you every hour. How hard would that be? Even give her change for the payphone.
When she calls, thank her for calling and wish her good luck.

I don't know, just my opinion.