Is this normal that wife has a tracking gps on husband?

Sort of? If you are in a trusting relationship who cares? It’s simply convenient to check where your spouse or kids are without having to wait for a response.

The only reason me and my wife don’t do it is because we don’t trust the apps not to scoop up our location data and sell it to everyone.

Doesn’t leaving location on drain phone battery at a higher rate?

Not really. Your phone is already doing location checks every few minutes for a variety of reasons, so it doesn’t really affect it unless you have rooted your phone and hunted down all the little bullshit things that trigger location checks.

You know you can just turn off location services right? Pretty sure even iPhone has the option

You can turn off higher level location services at the OS level, but at the radio level the cellular network will always need a precise enough location to handle tower handoffs and timing issues between the tower and phone, as well as modern beam forming techniques where the tower “aims” the signal at the phone. The simple act of the phone communicating with a specific tower tells the phone where it is (sometimes with surprisingly high precision).

911/emergency services also use more low level location techniques, but I’m pretty sure those functions don’t get called unless you dial an emergency number.