It is difficult to completely and totally stop your phone from being GPS located because the towers have been set to detect within a small range. However, you can try disabling the GPS settings so that you cannot be tracked unless for emergency purpose only.
do you have an android phone? there is an app called local or places in android phone..if you look at menu and location settings, there is an option called report location from this device which will report everywhere you go. so turn that off.. very interesting feature for unhealthy boyfriends :P