I'm sure you would be okay if your wife, now or in future, cheats on you and you cant do anything to investigate the issue.
In marriage faith in each other is #1 priority else everything starts falling apart, privacy b/w a married couple is next to non-existent. And esp. coming from a regressive culture where men are looking for excuses to marry as many women as they can, you cant blame a woman to keep an eye out for suspicious behavior. Woman are beings too, they do deserve equal treatment regardless of what you have been taught in your life.
I am a 100% sure, if the case was opposite here, i.e. man spying on her woman, it would be perfectly legal in this stupid justice system. Hell, I do remember in SA there was something like men having remote access to gps locators on their wife's phones. I dont know if its true, but coming from SA it must be.