I don't know if it's just me, but I'm sensing a little bit of unreliable narration here. Assuming the dog was as well-behaved as LW describes, the friend's reaction could certainly have been part of that power struggle LW says is happening between them. But I do wonder if LW's relationship with their boyfriend (and the dog) is subconsciously affecting their friendship with the friend, and they should discuss that.

(If I were the friend, I would have left the party, explaining that I thought I could handle the dog being present but I was wrong, that it was no one's fault, and that we'd catch up later.)

(That said, I don't like dogs very much. That's because I find, way more often than not, that the dog is nowhere near as well-behaved as the owner thinks. It's not the dog's fault it's not well-behaved, it's the owner's, but the result is still the same.)