Collaborating with A Spouse or Parent
The worst aspects of the relationship, the things I dislike the most, also surface in the collaboration. It is, sometimes, too much surfacing. One could try to minimize this by separating what is personal from what is not. Sometimes it helps me to put myself in a professional mode.
In my personal experience our collaboration suffered when there was a problem with our family. If I had been collaborating with somebody else, there would have been more chance to keep going because the friendly pressure of an outsider might have helped.