Ok so I don't want to go into the specifics because I know members of my husband's family read AIBU.
This is more a "how did you manage" to go no/low contact and "what were the repercussions" of going low/no contact with members of your spouse's family. The first may sound like a daft question but I think it's easier said than done to decide cut people off.
I have my own family's backing to reduce contact as much as possible with my husband's family after various things happened.