I agree with snowball! You are a grown woman, feel free to be in a bubble of hate all you want but as an adult and parent it is your responsibility to put your dd BEFORE your own feelings! What you have done is parental alienation and you will live to regret it! You have ruined any relationship your little girl had with her Daddy and as a result you will have caused a lifetime of issues for your dd.
Your little girl should feel able to go and enjoy spending time with her Daddy, without feeling guilty because she knows you hate him and the ow. In your shoes, I would apologise to your dd for running her Daddy down, tell her you were very sad and angry and as a result you lashed out and wanted to hurt her Daddy because you were hurt. I would tell her that you know she loves her Daddy, and that you don’t need her to be angry at him for you and that you don’t want her to feel guilty for enjoying time with her Daddy and ow.
Tell her you want her to be happy and that her happiness is more important to you than anything! Tell her it’s ok to be excited about becoming a big sister and that you are happy for her, so she doesn’t need to pretend to hate her new sibling or ow or her Daddy to protect you.
I know It’s not fair OP, your ex is a first class bastard and his ow is too! Your ex is a coward and should have left you before jumping into bed with his OW. She doesn’t have the prize though, unless you call it the booby prize - she gets a partner who she knows has the morals of an alley cat and has already betrayed his wife and child to shag about with an ow! Their relationship has shaky foundations because there can be no trust- so bringing a new baby into their relationship is the equivalent of chucking a grenade between them and setting it off.
However, if you handle the situation carefully, there is no reason why a new baby should put nails in the coffin of your dd’s relationship with her Daddy. Not unless you want it to, or your ex wants it to. If you do want it to then ask yourself whether you are considering your daughter above your own anger. If your ex is a shit Dad then he will put the nails in his own coffin, although it can’t be easy to continue his relationship with his little girl, when you have turned her against him.