Is it possible to not use iCloud without having issues with my Contacts?

This is the third time my Contact basically stopped working right because I'm not logged into iCloud. At this point you can't log into the iCloud without sharing your Computer password. I can't do that because I have confidential business information stored on my computer and I would be in violation of my client's trust.

This time, a Group in my Contacts is reverted to an old list from iCloud. This is a constantly changing group, and now I'm trying to send emails to people from 3 years ago. I am not connected to the cloud, but for some reason even if I open the group in my Contacts and click on Send email it goes to the iCloud list.

This is a serious problem in the software if it can't operate without being spied on.