Borrowed from advice for dealing with narcissists: become as uninteresting as a grey rock. Give one-word answers. Do not react to provocations. Do not share personal feelings. Your goal is not reconciliation but neutrality. Starve their access to your emotional reactions.
Stop trying to feel love or forgiveness. Aim instead for functional neutrality. Treat the hated person as you would a piece of dangerous machinery: with respect for its capacity to harm, but no emotional engagement. Speak only in transactional sentences: "Your turn for the bathroom." "Lights out at 11." layarxxipwsharingthesameroomwiththehate
Divorcing parents forced to share a house until a sale closes. Siblings who discover one sexually abused the other. Adult children forced to move back in with a parent whose politics or religion they consider evil. Borrowed from advice for dealing with narcissists: become
The family room becomes a battlefield without truce flags. One young woman who shared a bedroom with her sister after the sister had an affair with her fiancé described it: "We slept three feet apart. I fantasized about smothering her with a pillow every night for eight months. In the morning, we ate cereal at opposite ends of the table. The hate was the only thing we shared." Do not share personal feelings