I was adopted a long time ago when secrecy was assumed to be forever, by which I mean birth mothers ( & it was usually just mothers) and adoptive parents were assured complete confidentiality, no knock on the door in 18 years.
My adoptive mother was ashamed, bitter and angry that she did not conceive her own child. I know that phrase " her own " is problematic but that is how she would have said it.She was very abusive and used the adoption as a weapon. I won't put here the disgusting things she said but it was along ' bad blood' lines, I'm sure you can fill in the blanks.
NC all my adult life. Go me 
The law changed regarding obtaining adoption records and I contacted my birth mother 20 years ago.
Her initial reaction was one of horror, this was the thing she had been promised would not happen.
A relationship of sorts was forged however.I learned that my father had died young and without knowing of the pregnancy.
My BM and I would meet a couple of times a year.
Secrecy still hung over everything. She had a husband and children who knew nothing of me.
Years pass like this and then amazingly she tells me she has told her adult daughter. My excitement was short lived as in the next breath she tells me that my half sister doesn't want any contact. I honestly didn't know why she even told me this at all.
I was quite hurt and confused about this, I just couldn't imagine making that same choice if I were in her shoes.
Recently contact has dwindled and I'm sensing that soon I may not see her again.
This is her perogitive of course, I would be sorry if that were the case but it feels very much out of my control.
She has recently become a gm, my dh and I were unable to have children and I think she was avoiding me because of this.
One regret I have is that I didn't gleen every piece of information I could about my father. I was excited to meet her so it didn't seem a priority in the early days plus it was difficult to discuss these things as she would get visabily uncomfortable if I even broached it. His family , not parents probably but siblings nephews and neices are all out there somewhere and I would love to contact them.
I'm not a very emotional person but I can't watch " who do you think you are" and family history type things without feeling really jealous. I feel myself getting angry at not being acknowledged, rejected again really.
I might send her a message asking for all she knows about my father. I keep putting it off, I know she will be upset.
The thing is life is short, the years pass so quickly.
Its all a bit sad.
I'm just wondering if anyone out there has experienced anything similar and how you handled things.