Sister in law

About a month ago I got into a huge argument with my sister in law because she asked my husband if I had given away my daughters necklace to my sister. My sister in law gave that necklace to my daughter but I would never give that necklace away. I actually lost the necklace when we moved to our new house. And I had told her that but she thought the necklace my sister had on was the one she gave to my daughter. I got really upset when my husband came to me accusing me of giving the necklace away and telling me everything his sister had said. So I confronted her about it and asked her why she couldn’t come to me and asked me instead of going to my husband. All she told me was that’s my brother and I can tell him whatever I want. You’re nothing to me and you need to give me back that necklace and hung up the phone. My husband was so upset that I confronted her because he said I was overreacting. My sister in law and I had a great relationship before. We told each other everything. We were basically best friend. She knew all of my secrets and I knew all of hers. So that’s why I got upset because she could have came to me. So I feel like she was trying to get my husband against me. My mother in law called my husband asking him what I had done to his sister because was crying to her saying I screamed at her. He didn’t defend me at all. He actually took his sister side. My husband and I got into an argument because I told him he needs to pick its us or his family. I really just need advice I don’t know if I should leave him because i know I can’t ask him to stop talking to his family and I know he won’t anyways. Or just apologized even though I know I did nothing wrong. Also his family only calls my husband when his at work and when he gets out of work early he goes to his moms house. I feel so betrayed by him. I just don’t know what to do.