I don't want OS X to automatically switch spaces when i launch a new app
Same on OS X - unless you have an app specifically assigned to a Space.

Check what you have set for each app by right-clicking it in the dock…




All Desktops - the app will follow you wherever you go  
This Desktop - will change to show the Space number once assigned, then will always open in that Space.  
None - will open in whatever Space you're in at the time.


After comments:-
If you have Mission Control set to 'Displays have separate Spaces'&amp; 2 monitors, you will need a minimum of 3 Spaces before these options will become available to you.