If the girl that your boyfriend cheated on you with knew you were hanging out with him and sent him a Snapchat that said "This is for your eyes only and you can't show anyone else." Would you be angry & would you say the girl is just trying to upset you?

If you need clarity, here's what happened.

After cheating on his girlfriend of 7 years for the third time, a guy I know supposedly cut off his friendship with the most recent girl he messed around with. While out of town at an event with his girlfriend, he received a message from her on Snapchat that she had something to show him and he couldn't show anyone else. For his eyes only. His girlfriend got extremely upset because he allowed the other chick to send it and he viewed it. He also still talks to the other girl daily though he says their friendship is over. He has not blocked her or removed her so she can't contact him or send him photos. He claims his girlfriend overreacted, that the other girl was not intentionally trying to upset her, and that she can't tell him to block the girl he cheated with. The kicker here is that the photo was of a crystal. A rock. Not the kind of thing you tell someone to not show anyone. Was she intentionally trying to make it sound like nudes? Was she trying to get under the girlfriend's skin because he just told her they can't be friends since he wants to fix his relationship? Should he remove and block the other girl entirely? Would you take back someone after their third time cheating even if you had been together for a long time?