I lied to my daughters about their dad
Why would you lie to them about their dad?
He was not the man I thought he was.
While it is your decision what to tell them about their dad, just remember that they may find out the real details when they get older.
It's my business.
It absolutely is your call to make, just keep in mind how they'll feel if they find out years from now that you've been lying the whole time. But, if the lie is for the safety of your kids, I think that's understandable.