Throwaway Account

Okay, cutting to the chase my half sister "Kelly" (32f) caught my other half sister "Lily" (29f) in bed with her husband and Lily is having a baby who's paternity is in question, and from where I (19f) from sitting this is all delicious.

Now before you all come at me in the comments, here's some context:

CONTEXT: I am my parents' only child together. Kelly and Lily are my half siblings via my dad who divorced their mom. A year after the divorced was finalized he met my mom who had just moved in from another state, so my mom was never the other woman. Didn't stop Kelly and Lily's mom from painting it that way and they believed her. Kelly and Lily didn't like my mom and made it known. They weren't happy when they found out that I was coming and have told me so themselves that they wished bad things to happen to my mom while she was pregnant so I wouldn't exist when I was a child.

Because of this, I am not close to my sisters at ALL and while they have calmed down with age, there's too much negative history there. For the longest time Kelly and Lily only considered themselves as each other's sister, while I was just their dad's other kid. That's fine by me, my mom has another daughter from a previous relationship that I love and trust, and I'm fine with just having her. When Kelly got engaged I was invited to the wedding and only went to appease my dad as I'm sure Kelly only invited me for the same reason. She made it a point to sit me far away from the rest of the family but it was cool since I didn't get a gift and left early. Although not before sitting through Lily's lovely MOH speech talking about the importance of family and fidelity (oh the irony). That was 5 years ago and I have a copy of the recording of said speech.

Kelly, Lily, and I don't follow each other on social media but because of our shared paternal side we have a lot of mutuals and will occasionally see what the other posts. When I heard through word of mouth of what happened, I was shocked and in disbelief. I wanted to test to see if it was real but in a super petty way so I posted a clip of Lily's speech and innocently captioned it a message asking if anyone knew/remembered any details about where I could the dress because I wanted to buy one just like it but in a different color.

I got a message from Kelly (surprised she had my number) and she started to rage at me. I spent on hour on the phone with her pointing out that we never talk so I didn't know that my post would touch a nerve. That seemed to calm her down and she just vented to me and I was like "yeah it sucks when you have a sister who actively hurts you." Nothing clicked. I immediately took down the post after the call and Kelly shot me a friend request. Then I got another one from Lily the next day. My sister "Roberta" (32f) thinks that I should either just block them and continue with our estranged relationship as is or help to fix it, but I kinda just want to stick around for the drama. However, Roberta's words are starting to get to me so I have to ask AITAH?