If this person is upset, I think I'd mention to the boss that you spilled the beans so they could be prepared....
I've learned after many years to just keep my yap shut....I tended to be like that and my daughter is the same...open mouth; insert foot....you said it yourself in one of your last paragraphs:
that I never think about first
That's key....take a few minutes to think before you talk so you understand any ramifications....