Your daughter wants her father to be part of her life because he is her father. She has a right to have her father in her life. His second wife probably comes with the territory.

What do you mean by saying that most women would not let the father be part of the daughter's life? When she was a minor, he had a legal right to be part of her life. Now that she is an adult, she makes the decisions on whether to let him be part of her life. In both cases you are not in the picture: the legal right was independent of you and her own decisionmaking is independent of you. It might hurt but it is the reality.

It is not fair to the daughter to expect her to take your side.

Please post about your anger, resentment, and hurt, and perhaps seek therapy for healing, but do not expect the daughter, or, in the future, the grandchildren, to take sides.