In-law rant

Let me start by saying my husband and I have been married for 2 years and ttc for over 2 years. We have reached the point we have seemed fertility help. My so-called sil (no married just baby momma) has made comments that there is something wrong with me or something wrong with my husband. We have done iui’s recently. Sil decided to ask me who is paying for the procedures. I am the one paying for them. She is rude and disrespectful. She has 3 kids and only has custody of 1! My in laws treat her like a queen. My mil has told me what she says about me and my infertility. Which pisses me off who is there right mind wants to hurt people. I told my husband the next time she (baby momma) says one thing out of line I will react! My husband is a non drama person. We are currently avoiding his family. I feel sorry for my husband- he just says that is the way they are. I am so thankful I have a wonderful family. Anyone deal with toxic in laws?