Bored Panda quotes FSC on what happens when siblings choose partners

“AITA For Refusing To Babysit After My Sister Demanded I Stop Bringing My BF To Family Events?”

Author of Brothers, Sisters, Strangers: Sibling Estrangement and the Road to Reconciliation, Fern Schumer Chapman, suggested that one of the siblings choosing a partner can be a perilous moment in their relationship. “A new partner may feel threatened by, or jealous of, closeness between brothers and sisters…”

https://www.boredpanda.com/man-refuses-babysit-homophobic-sisters-kid/