I agree with Cory.
Sometimes I have had a bad day, the DC have been playing up and might overreact to a situation. DH will step in to
- Calm me down - give me a "timeout"
- Stop me flying off the handle
- Stop me handing out punishments that are just too harsh
- Mediate between the DC and myself
This can work in both ways. DH was a grumpy bugger yesterday and was narky with the DC so I called him on it, in front of the DC.
It is perfectly ok for the DC to see that their parents disagree sometimes, even about their behaviour.
And that if a parent is being unfair that the other parent will not just automatically back him/her. This would lead to a them and us scenario that I want to avoid.