In order to shield ourselves from admitting fault, we instead attach this one incident to a much larger story.
That is why when we argue with family or spouses or even a stranger at the DMV, it can turn into a much bigger argument than it should. We are hauling extra baggage into the narrative. Carrying it forward instead of focusing on what is actually happening.
What you probably did is leave the thermostat on, not sabotage the whole relationship.