On your own head be it! 

Idiom

used to tell someone that they will have to take full responsibility for what they plan to do

I am telling you, don't get married to her, she is a control freak but if you do then, on your own head be it!

If you want to quit a high-paying job to chase after some fantasy of being a travel writer, then on your own head be it!

On your own head be it! by Zami Karzai September 13, 2018

on your own head be it

used to tell someone that they will have to take full responsibility for what they plan to do

At risk of being impertinent, if you make her head of the company, on your own head be it.

on your own head be it by therma2000 April 9, 2012