desktop shared across macs

Only recently experienced this where my desktop is now on iCloud and the same appears on all my computers.

Have been using iCloud for file storage for many years, with each computer having its own desktop (one for travelling, one for the office etc). Now all the same and a real pain. All advice I have seen is to turn off desktop and document sharing. I want the documents not the desktop- how? it worked fine until a few weeks back. Just updated the operating system on one of my computers and its joined the shared desk top. really annoying.