My girlfriend had a dream where she knowingly cheated on me with her best guy friend?

I love her very much, and she loves me very much, no doubt, and we dont have really any problems in our relationship. They say that they view each other as siblings. She assured me that she would never cheat on me, and i believe her. but i just thought it was odd. Tonight his girlfriend left him and he called my girlfriend and cried about it and vented to her, and she comforted him for a whole hour, and i know i'm probably overthinking it but i always worry a little in the back of my head. What do you think?