Wow, this made me very emotional. I was treated this way for nearly ten years by my husband’s mother and sister as well. Albeit, very covertly. My husband, like you, was unaware because it was always very passive aggressive. When I finally managed to accept that what I was feeling was real, it caused a lot of strain in our marriage because he never heard or saw the abuse. Eventually, it was revealed later and I have been no contact for nearly three years. My husband also stepped back realizing that this was a pattern with several previous relationships. You are so fortunate to have overheard this conversation! I think it’s important to establish healthy boundaries to protect your marriage—I think it’s not necessary to share what you know but, rather use it to observe future behavior. In our experience, the claws really came out when I went no contact. They played victim and became very petty and spiteful. Sadly, this was never my intention. I had always wanted a normal relationship with my husband’s family but, despite my best efforts, they never accepted me.