Contradicting your partner in front of the kids
ADHD parent behaviour
What to do right now
You disagreed with what your partner just did or said, and your child saw it. The split is now visible. Don't compound it — hold the current position, even if it's not your preference. "Okay, what Dad said stands. We can talk about it later." Later means later. After the kids are in bed, not after dinner.
What your brain just did
Your body
You reacted before you could coordinate with your partner. The words were out before you processed that they'd already set a boundary.
Your brain
ADHD impulsivity applies to disagreement too. Your brain registered something that felt wrong in your partner's approach and responded before the executive function system could weigh the context. The impulse to correct felt more urgent than the need for a united front.
What this did
Your child just learned the boundary has a gap. Two adults disagreeing in front of a child about rules gives the child a negotiation opportunity that undermines both of you. Discuss it privately, then present one position.