My husband has met his birth mother in last 5 years and he has several half siblings. He was adopted due to her being a v young mum.
His adoptive parents have not met his real mum and haven't suggested that they do but they're happy for him.
We all get on well but my dh and I do have regular eye-rolling sessions at the wider family and their restricted and often ignorant opinions. We'd never say anything as they all have a lot of love for each other and it would be rude coming as outsiders.
But then we often do the same with our "real" parents!!
We are by no means involved with them to the extent that they are with each other, they spend a lot of time talking, messaging and being together. We tend to go to birthdays and christenings and then arrange a get together every couple of months. I talk to some I them via fb. That's not his thing.
My husband is quiet when around them as he is usually quite opinionated! I think he just wants to get on with them and enjoy having a bigger family. He's not an overtly emotional person....nurture not nature!
He is still v close to his dad and sibling (adoptive) and they talk most days. And his mum is the most chilled about it all and asks lots of questions about his half siblings and family tree.
So his is a story that's worked out on its own way. I don't think he had any expectations, he just wanted I know who his family is. He sees the rest as a bonus! I think you can't expect a normal family relationship but any kind of friendship is a huge bonus!
I expect the adoptive and real families will meet one day!