So tired of my SIL and BIL

My SIL and BIL are so fucking annoying! When I got engaged to my SO, she got engaged not too long afterwards. She found out we were trying for a baby after I told my MIL since she asked when we'd start our family. After she found out, she was pregnant after. I got over it, and conceived a few months after. When I announced it and announced my gender revealing party, she announces she's having a barbecue at her house the same day. She then got pissed off when people told her they wouldn't be able to make it to hers because they saw mines first. She was mad at my husband and I saying everything always has to be about us and saying how we always ruin stuff for her. We ignored her childish behavior and she tells her mom we wished death on her baby when we would NEVER do that no matter the situation. Now my MIL doesn't want to come to my gender reveal party. My BIL and husband had a big argument over it too. I'm trying not to stress about it. After this party we're looking into moving away.