BF saw rando msg from guy on snapchat

kelly

So some random guy idk added me on Snapchat and apparently I added him previously but I have no recollection as to why I did it or when cause I have no idea who he is. Boyfriend saw it and thinks I did it on purpose. I have no clue who this guy is and my boyfriend is mad at me. All I can think is maybe I added them by accident or to see who it was but nothing romantic or sexual.