My sister (25) and I (20) were at her apartment when she realized our mom (45) took off her find my friends location so we couldn’t see where she was. Some background info, my mom is on a strict diet and lost 15+ pounds and has always been obsessed with her appearance. She’s been buying new clothes, and has had work drama for the past 2 years. She’s let her workplace consume her, she’s agitated everyday from work and lets the toxicity of her coworkers get to her.

But lately for the past month or so she doesn’t come home right away and I notice she parks her car in random spots in our neighborhood for hours just to talk with whoever in the car.

Yesterday, my sister called her bc for the first time ever, she turned off her location and our mom got flustered when asked why. From what my sister said (I was asleep on her couch), she asked our mom where she was at and she said Wendy’s picking up food. My mom has been strict for weeks and refuses to get fast food with us so it was odd. She got angry at my sister for asking where she was and ended the call. My sister called her again via face time and she answered. Long story short, our mom refused to show the front passenger seat and only showed her one side of the car. She ended the call when she confronted her. My sister CALLED AGAIN and she picked up minutes later and was arguing with her. Sister saw a blue car in the rear view mirror and calls her out on why she’s alone with locations turned off in a parking lot where it’s known for being kinda hidden and empty near the highway in our town, mom freaks out and ends the call.

Doesn’t stop there. This morning I realized she went to work and she took my car keys. I leave them in the same drawer and they were gone. She forgot we had a spare. I drove to her workplace and lo and behold the blue car and hers were there. We found out the cars owner was a guy (we have police connections so we ran the plate number) and he’s a coworker my mom talks to.

Mom came home earlier and I calmly confronted her. I asked her why she had her location off and she yelled at me saying she didn’t have to tell me anything. Then I asked her why she was with a guy named John (fake name) and she said and I quote, “Who? I don’t know him!” She’s told us about him multiple times before, to me and my dad.

What’s worse, when I first brought this up to her, she said straight to my face, “If you tell your father this, he’s going to divorce me,” I was so shocked she said that I asked her to repeat what she said, and she hit me with the “what!? I never said that!”

“you’re going to ruin everything if you tell him,” “you and your sister are trying to make drama”

I asked her again why she was in the parking lot with John and she kept changing her story, at one point she said she was never at the parking lot and was at work.

Oh, and she did take my keys. She tried to gaslight me saying they were in the drawer but left them on the counter with HER keys as well. Then she told me she had mistakenly grabbed them in the morning thinking they were hers. We have different cars and keys!

If you made it this far, I’m not sure what to do. She’s repeatedly told me she didn’t do anything. But refuses to answer why her location was off and why she was with John. When I brought up his name she said I would get her divorced and that my dad should never know. But didn’t explicitly say what she did. I let the situation drop, my dad knows but I’ve only told him that she had her location off when he was working over time and that she was with John possibly. he’s not confrontational. She’s the abuser in the relationship (mentally) and I hope I’m really wrong but I simply do not trust her and I’m debating if I should keep fighting her on this or if I should let it lie? My dad listened to what I had to say, and just nodded and walked away. I think it’s in the back of his mind now, and he didn’t believe my mom about the key situation when I brought it up during dinner. But nothing else has been discussed my family hates communication and we’re now acting like everything is fine and nothing happened, I could have told him more on how she was changing her story, but I am afraid that I might be wrong and I feel guilty that I don’t trust a word she says. So, aita for telling our dad?

(Sorry for the long post)

TLDR: My sister and I noticed our mom turned off her location for the first time ever. We found out she was with a male coworker and we confronted her, she lied, changed her story multiple times, and even warned me not to tell our dad because it would "ruin everything." She tried to gaslight me about taking my car keys too. I told my dad a small part of it, and now my family is pretending like nothing’s wrong. AITA for telling him something when my mom begged me not to? Should I let it go or push it further?