Don't threaten or talk divorce yourself... YOu want her to feel like there may be a window open there still...

Be CIVIL, don't name call or shout... You talk to her like you would a teenage daughter who's been breaking curfew.. That's it...

You woudln't name call or yell at your kid, you would just stand there civil and calm, but FIRM and bring the consequences down... and NOT BACK DOWN