You were married to Kunikida for some time now and you were an important member of the Armed Detective Agency, so the port mafia uses that to their advantage

Kunikida: “Hey baby, while your out can you get me the notebook from the guy later?”

You nod and head out so while your out one of the mafia members stabs you in the chest 10 times, you lie there bleeding but the next day they see you walking with Kunikida like nothing ever happened