You are feeling mom guilt over this? You have some tough days ahead. I always wonder why the wife's standard (perfection) is the default setting?

Men, and I say this having been a male for awhile now, are not shooting for perfection. Or anything close.

Your son was not harmed in any way. What would you have said if the dentist called and had to cancel? Would you have accused the dentist of harming your son?

Your husband had a minor screw up. Let him handle it.