Navigating sibling relationships into adulthood is complicated enough on its own. But it's a completely different animal when they date or marry someone you don't get along with.
On one hand, who your sibling loves is their choice and if you're close and value each other you should be able to get past differences with their partner. But in some cases, they choose someone so toxic it's not worth the effort, and your in-law's behavior clouds and mutates the good things about your sibling.
"AITA for cutting my sister and future nephew out of my life over a "joke" her husband made?"