So I've heard a lot about phone tracking apps being something inappropriate and BAD in general. However...
Well, what's so bad about being aware of where your kid is or what messages they send and receive? You know that for sure - these days, your online life is in greater danger than your offline one is. Many of my friends actually use parental control apps to be sure their kids aren't being bullied or involved in any kind of internet scam.
Same goes with trust and honesty issues between partners. If you have nothing to hide, you have nothing to worry about, right? So, I don't see anything inappropriate in using tracking tools either.
Another point is the quality and reliability of the apps you decide to use. That's why it's important to make some kind of research - afaik on platforms like getcellphonespy a team of competent specialists review different apps and provide some tips on how to benefit from using those. So, research is always appreciated.