I would agree that you are trying to hard to discern exactly what happened when you need to look at the bottom line.
But, to address your comment about cowering and remembering when your parents yelled:
yes, that is called a trigger. And it's real. Your mind gets sent back to the or a set, of original trauma, and your physiological reactions mimic what it felt like back then. This is why you would likely benefit from therapy, and need to distance yourself as much as you can from the triggers.
And, for what it's worth, I say contract-schmontract. He's a kid. He knows the rules. He's still gonna ask. It's your job to enforce them consistently.