My boyfriend and I went to the beach a couple weeks back. Although I felt uncomfortable with it based on past behaviors, the only option was to allow his mother to pet sit our dogs, staying in the house. When I got back, I found that she had sorted our mail into a neat filing system in milk crates. Oddball behavior, but something I was willing to let slide.

Fast forward to last night. I went to file some new incoming mail and noticed that things had been opened that I had no recollection of opening. These items had sticky notes in her handwriting categorizing them. With these particular items, she had no way of knowing what they were unless she took the letter all the way out to look. I was (and still am) horrified.

So I decided to be a big girl and call her to ask. She denied it straight away. When I said, “Okay, I must be going crazy then, because I don’t remember opening them and boyfriend says it wasn’t him.” She then admitted to opening a corner to “peek” to make sure she had her categories right. And I lost all my guts in that moment and let her lie to my face. I say she lied because I went back and checked the items were fully open, not a corner opened.

I am so disgusted with this behavior. She has overstepped many boundaries in the past and my boyfriend has done a fantastic job of doing what he can to keep her in check. He is willing to talk to her about this issue, but I almost want to confront her again just for my own mental health.

Things cannot be the same with her after this. I’m still in shock and trying to process, but I know that for sure.

TL;DR: My MIL opened my mail and read it so she could organize it for me. I am disgusted and sad and at a loss for what to do.

ETA: Boyfriend and I have been together for 5 years and have one 6 month old together. Bad behavior started when I got pregnant. MIL also walks all over SIL and invades her privacy too.