split the blanket

verb2

1. •
   To terminate a marriage or marriage-like relationship; to divorce or permanently separate.

   • After that, Mrs. Transome said that she knew it was time to "split the blanket." She has put up with his temperamental behavior and alcoholism for years. — 2002
2. •
   To dissolve a partnership.

   • "Well, I reckon that splits the blanket," said Will. "Now he knows we ain't buyin' his shakedown, I reckon he'll loose them pet Comanches on us." — 1992