Vapo, this might be a cultural difference, but Ginger's advice is inline with the parenting and adoption advice given here in the US for the past two-plus decades.

It's almost impossible for someone to go their whole life these days and not realize they are adopted (if they are), so then they are dealing not just with whatever feelings they have about the adoption, but also with feelings of betrayal directed toward the adoptive parents.

The advice is to tell kids from very early on--much younger than East's daughter.

I absolutely agree with you that East is her father, but he can emphasize that while still telling her the truth about when he came into her life.

Me: 44
H: 44
Kids: 20, 16, 16, and 10
Together/Married: 22 years
H announced he was emotionally detached and considering D: 4/4/16
H announced he is going to try to stay and reconnect: 5/1/16