Asking Eric: Why is my sister trying to drive a wedge between me and our newfound half-siblings?

A letter writer is consulting Asking Eric because their sister, Jodie, is attempting to drive a wedge between them and their newly discovered half-siblings. While the writer seeks to build a functional relationship based on dignity and the possibility of personal change, Jodie is actively sabotaging these bonds by conducting background checks and snooping for sordid details from their past. The writer is now undecided about excluding Jodie or including her in future gatherings.