You screwed up. You promised not to tell anyone, and you went ahead and did it anyway. That was not cool, despite how close you think your brother is to this person. It was not your place.
Your opinion would be just as biased.
Dude. I get where you are coming from, but really? That was a pretty rude thing for you to say.
That isn't what happened here. He is upset that you broke your promise not to tell anyone.
That's reasonable. I don't see why you have a problem with this.
Looked, you goofed and now you're mad that he called you out on it. He's being extreme with worrying what your hypothetical wife might do, yes. But you also could use a dose of accountability here, which I don't see at all in your post.