Exactly how would your ex find you using the cars GPS?? My wife has an 07 Accent and as far as I know there is NO GPS anything in that model of Accent!?
If you're truly concerned, call the dealership and ask to speak to the service manager and ask him if the car came equipped with anything like that. But I'm sure you have nothing to worry about.
2007 Hyundai Accent
2004 Hyundai Accent GT
1991 Isuzu Impulse RS
2007 Ford E-250