The speaker is caught in a painful relationship and can't quite explain why they remain in it. The opening line borrows the term "Stockholm Syndrome" from other people ("They say"), suggesting outsiders see the speaker as a captive who has grown attached to the person holding them. The speaker doesn't fully accept or reject that label. They simply admit they still don't want to leave.
Leaving, it turns out, didn't bring the relief they expected. It hurt more than they realised, and now they wonder if they're just obsessing over how the other person made them feel. The last stanza is the most honest. The speaker finds a strange excitement in the pain and has grown so used to it that anything else feels frightening. The poem ends on two unanswered questions, "Is this wrong? Am I wrong?", which leaves a mood of confusion, vulnerability, and self-doubt. It reads like a private thought the speaker is still trying to work out.