inseparable relationship (undesirable); hard-to-break bond
Refers to a relationship that is difficult to sever despite being unwanted, often due to shared history, obligation, or bad luck. Carries a negative, resigned tone.
I have an inseparable yet undesirable relationship with that person; I've tried to cut ties many times but we end up meeting again.
腐れ縁の友達って、なんだかんだで長く続くよね。
Friends you can't seem to shake off, for better or worse, tend to last a long time.