come undone

verb2

1. •
   To become disintegrated, to break into parts or pieces.

   • I never seen you looking so bad, my funky one / You tell me that your super fine mind has come undone — 1974
2. •
   (figurative) To come to ruin, to fail; to lose one's composure or self-control.

   • He came undone when his wife refused to support him.