Can r/gonewild help me with a sexy misunderstanding?

21 y/o male here. So a while back I float the idea to my girlfriend (a few days away from our 8th month now) for us to do a request thread here. Initially she kind of liked the idea and thought it might be hot. Fast forward to today and when the subject comes up again she does a full 180 and tells me that, "...of all the flaws of my exes, not one of them would have let me think of the idea of showing off my body to other guys." I tried to explain to her the inherent difference between me being ok with her sending naked pictures of herself to other guys and the two of us participating in anonymous exhibitionism (the plan was to wear superhero masks). Now she is angry with me. Am I in the wrong here? Advice?