The die has been cast British American idiom
'The die have been cast' or 'the die is cast' that are the same meaning. To say the die is cast is to suggest that the point of return is past a process. Die refers to a numbered cube used in gaming in the metaphorical sentence (the singular of dice), and cast means thrown.
A circumstance in which decisions or decisions have been finalized and can not be changed
The die was cast from the moment the negotiations failed and war was inevitable.
At the moment my dismissal has been confirmed, the die is cast.
This expression comes from a Latin phrase that Julius Caesar said when he crossed the river Rubicon and became involved in a civil war in 49 BCE.
To tell someone the truth about something that they had not understood or received false information
I have to set my wife straight about what happened yesterday.