on head

on (one's) (own) head

Being one's sole responsibility to bear. I won't rat you out, but if you get caught cheating it's on your own head! She's the one who cheated, so in my book, their marital troubles are on her head.
See also: head, on
Farlex Dictionary of Idioms.

on someone's head

Fig. [for something negative] belonging only to one person or group. All the blame fell on their heads. I don't think that all the criticism should be on my head.
See also: head, on
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • on (one's) (own) head
  • on one's head
  • just deserts
  • the heart wants what it wants
  • caught between the devil and the deep blue sea
  • get taken to the cleaners (by someone)
  • caveat
  • caveat emptor
  • a/one side of the story
  • a/one side of the story/picture