The father found it difficult to accept the non-biological daughter and he separated from his wife. The Royal Family is buttressed in many ways, though not it seems enough for three of the four children to have experienced failed marriages.
Steve isn't that how it came to light, the father of one of the girls suspected something wasn't right?
Many people have failed marriages. The queen had four children and 3/4 ended in failure

But Ann and Charles are now happily married as far as anyone knows.
What about all the thousands of women who died in childbirth 100 or so years ago. Their babies were brought up by others. Did they all suffer primal screams?
Prisons are stuffed full with people brought up in care homes not people adopted by middle class families.