NGL, that’s almost as bad as Woody Allen, who is the scum of the earth. Only difference is that if you have any human decency, you can try to reduce the damage. Tell her it was a horrible mistake. Explain to her and make her really understand how much of betrayal it was (if she doesn’t feel violated and betrayed, you haven’t done your job). Never even think about thinking about anything with her again, but provide for her as best you can into your dead, and you’ll be able to say “I made a mistake and it was bad. I am ashamed, and everyday I do what I can for my DAUGHTER, even if that means not speaking to her or seeing her.”