How to prevent Windows 10 from tethering to my phone?

I have an iPhone, and recently, every time I plug it in to charge via USB on my desktop machine, Windows 10 starts using my phone as a networking tether.

1. My Win 10 machine has internet access so I dont want to go through my phone.
2. When it tethers, the route tables get screwed up and traffic that needs to go out over existing routes gets screwed up by the new network interface.

I cant seem to figure out how to disable automatic tethering in Win 10

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