Champion sired two children, boy and girl, the girl is sick with autism so he told his wife she died and gave it to the nurse that she helped him in the process of birth and asked her to put in front of Mljye for orphans because they will die, but the nurse Ahtfezh the girl child and raised and taken to send photos to her father every year and tell him that his daughter is not dead

Are you sure it was a boy and girl, this sounds like the plot from the movie PRINCESS DAISY but it was twin girls and one was brain damaged from the birth, later the wife finds out from the nurse that he lied about the baby being born dead, and leaves him taking both girls back to America with her He was a Champion Polo Player (Russian Prince) and she was an American film star. The actors were
Lindsay Wagner and Stacy Keach.
This is only my opinion, it may not be the movie you are looking for.