Not much more to add really.
All of the games I play on Steam only use one screen, is there any way to have my desktop active on the second screen or is this not possible?
Yes it's possible, you need "Actual Multiple Monitors"
and here is the video of how to configure it: https://www.youtube.com/watch?v=hqqZlAlM0AI
It is possible using desktop virtualization software like SoftXpand
See video ~ https://www.youtube.com/watch?v=a6IarpedJ60
That's the only realistic way I can see it working without Steam minimizing whilst you are using the keyboard/mouse on the second monitor.