AITA for showing my bragging about my girlfriends nudes

I (M24) and my girlfriend (F20) have been dating for a few months. I’ve known her since high school and we recently got together. Things are getting serious, and since I was away for work last week, I asked her for some private photos to tide me over. They were so stunning that I had to show my buddy that I work with. He shared my sentiments and very respectfully asked me to share them. I trust this guy with my life (we’ve been friends for years) and so I obviously sent him one or two. A couple days later I come to find out that my friend’s girlfriend discovered the photos and told my girlfriend. She was livid and cussed me out in front of my friends when I returned home. I told her that her reaction was over the top and that it wasn’t a big deal because my friend was trustworthy and it was just because she was so beautiful. Am I the asshole?