As a Project Leader, I have access to a couple of project accounts in addition to my personal account, so I know how confusing your situation can be.
One solution would be to buy a second computer. Assuming you don't want to do that, I suggest that you try a workaround that I have found helpful: Install a second browser application on your computer and create a rule where you always edit WikiTree in one browser (for example, Google Chrome) and your spouse always edits in the other browser (for example, Safari).