It's so much more than just a mistake. It wasn't a mistake when you opened the door and let her in. It was not "bad judgment" that made you delete every conversation you have with her. It was not a mistake when you chose to talk to her every single day and continuously lied straight to my face whenever I asked who you were talking to. Your continuous betrayal was not a one-time mistake - that was a choice you made every day. A continuous choice to abandon us.
So I stopped asking questions; I stopped digging deeper. Because you don't see the world as I do, and it's more clear to me now, that you don't see yourself at all.