Spotify launches on multiple devices simultaneously

[epoch71]

Plan

Premium

Country

UK 

Device

iPhone 6p / Google Nexus 6p / Huawei Watch

Operating System

iOS 12 / Android 8.1

 My Question or Issue

I primarily listen to Spotify using my iPhone.  I also have Spotify installed on my Nexus 6p.

Whenever I launch Spotify on the iPhone and start playing tracks the app also launches on the Android too, and starts (silently) playing the same track.  And consequently the Android watch picks up on this and displays the playing track too.  How do I prevent the other devices from launching Spotify when I don't need them to?