A relational pattern of organizing your sense of worth, mood, and choices around managing another person — most often someone in active dysfunction. Common partner-side response to NPD/BPD relationships; often pre-dates the current relationship.
You can tell from your partner's footfall whether dinner is going to be calm or not. You've stopped knowing what you'd want for a Saturday without managing for them. Codependency isn't a character flaw — it's a learned survival strategy, and it loosens.