My brother in law and partner hate me

3 years ago when my husband and I were still dating, we threw a party for his parents at our house. His siblings obviously helped and were involved but for time purposes and the fact that they are all boys with no initiative, I took the reigns lol. We had 2 weeks to pull it off and we did! My BIL girlfriend was always on the quiet side but after that party happened she suddenly hated me. Gave me dirty looks, wouldn’t speak to me if I spoke to her. Huffed and puffed under her breath when I would walk by. Bizarre behavior for someone who always acted shy… then my BIL started doing the same. He stopped talking to me and even his own bother. It’s been 3 years. Last year at my wedding they caused a lot of drama because of their hatred towards me. My FIL told me finally that they were mad MY wedding day was happening and all about me. And he said the party was an issue to her because she didn’t like that I was planning it and calling the shots. She claimed I said something mean or rude to her but that’s a lie because we barely spoke (remember she’s “shy”) and I’m honestly not a mean person! Since that day this girl has been a bully. She waits until no one is looking and then does petty things that have me in tears later. I’m sensitive but still lol. But I’ve let it go over and over. What was I supposed to do? Start something by calling her out? Run to my boyfriend’s parents crying and whining? So I’ve stayed silent all this time. My FIL hates her and has been vocal that everyone needs to just sit down and talk but I see it being worse. She just married my BIL this past weekend and I’ve never been so devastated. I see the behavior worsening because now she feels safe and comfortable being legally bounded. My husband and I had a baby soon after marriage and with my baby being 5 months old, my BIL and her still haven’t even held him… let alone even look at him. It’s heartbreaking! Their uncalled anger is being taken out on a sweet baby. Point is they are angry people. My FIL says she’s just jealous of me. She’s the only girl in her family so he thinks she believes being the number 1 girl in all families is important. I wanted to be her friend, not compete with her. I hate that my husbands family thinks she’s so sweet and innocent and I silently sit there battling my inner thoughts where I just want them to know the truth!! But silent I stay. Point to the ramble, I got an immature annon message on IG saying she shit talks me and the family. FINALLY!! But yet I sit here with a way to bring her down and after 3 years of being silent, I’m like well I still can’t say anything because somehow I’ll be the bad guy. Would you respond to get a few more details and tell the family? Or continue to suffer with family drama and hatred forever? She has split 2 brothers apart and she has destroyed what could have been a relationship with an uncle and his SIL and nieces and nephews. I’m just so sad and SOOO angry. Thoughts??