There is are so many feelings about adoption within families it can be surprising about how others react to any side of the adoption triad. I grew up with Adoption as a fact of life in my family. I had so many cousins who were adopted that I thought I was the "different" kid in my family--after all I was not picked!
But, there was a time when my grandmother very deeply hurt my aunt. There is this Item that has been passed down to the "Oldest" female of each generation. My grandmother had it and I was about 15 when she announced that she was giving it to me and not my aunt and cited the reason to be that my aunt might not give it to me and might give it to my other female cousin and then it wouldn't be in the family anymore because my cousin was adopted!

Anyway, I have it now and frankly it lost most of its value in my heart over that family fall out event!
That cousin is in reunion with her birthfamily now and has been for about 2 years. She has developed a deep connection with two of her siblings, but has had a difficult time with her birthmother due to birthmom being an alcoholic. My Aunt has done very well with the reunion and has even met my cousins birthmother. For my aunt the hardest part was when she realized that her grandchildren had another grandmother!
I sort of felt that way when my biological children met their Grandparents and I was told my daughter looks just like the grandmother and biological aunt! I had always felt my daughter looked like my father...My ex has only been in reunion since about May. He has not and does not plan to tell his adoptive mother that he is in reunion. She is 79 and in frail health and always had a strong negative attitude about her two adopted children looking for their birthmothers. She has actually asked them to wait until she is dead..... My sister-in-law was also married to an adopted person and he reunited in the late 80's with his family. His reunion was a failure and he ended up being cheated by his biological siblings in some business deal they cooked up.
For my own children is has been wonderful for them to have the other half of their genetic history. I think being the mother of children born to an adopted person made me experience some of the same kinds of feelings about genetics that an average adopted person might feel. It WAS strange to only KNOW one side of the medical history. I remember filling out the paperwork and answering on my side and leaving question marks on the other side of the family history except for what we knew about their father.
It has been very odd however for my biological children who have just about one of the MOST Scottish sounding surnames to realize there is not one drop of Scottish in them.... But, instead American Indian and English! WHAT? My biological children turn out to be nearly a full 1/4 American Indian.... WOW who would have ever guessed that and I thought it was the dark Irish showing up! Oh, well now that I look at my adult biological children I do see the American Indian in them....who would have even thought that?
I was with my ex for 15 years. He had several "Adoption Stories" he had made up over the years. Some were very sad and needed professional help if only I had understood more back then! I am actually very glad he has reunited. Many of the "stories" he had made up were not healthy and from everything that I am able to understand his birthparents made the only choice they could during that Era and they did so because they loved him enough to let him have the life he had. Which for the most part was a pampered and well off life.
Families today are so complex sometimes. I think I have LESS concern about a reunion for my children due to the broad definition of family that I have lived. I think that any parent who has had a divorce and every other weekend visitations with the other parent makes it a lot less scary to think about the birthfamily. As an adoptive mother my children had a slightly different story in that they were taken from their birthmother because she was not safe and not able to keep her children safe. But, even in this case I do feel that if or when there is contact I will have done a great job as a mother of these children that they will be able to deal with whatever the reunion might end up being.
I think that as a mother my main objective is to Raise Healthy Adults because in my reality it is the relationship I have with my Adult children that I will value the most. My goal is that each of my children be who they are and feel safe enough to let me know who they are without fear that I would reject them....my love is unconditional but I still will tell you what I think....If my little ones grow up and want a reunion I will be supportive and all I can do now is Pray for their birthmother and hope that when there is a reunion that it is a positive and healthy one.