My family history is another of children being born out of wedlock and raised as a sibling.
My Nan had a son after being raped by a family member. He was raised by her parents as her "brother". She left him in Scotland when she moved over here with my Pop, Dad and Uncle in '66.
I found out that Nan and Pop were married after my Uncle was born in '57, I was doing our family tree and it came as a surprise!
My Aunt had a daughter in the early 70s who was adopted out, she found her recently.
When my parent's were first married, Dad told Mum he thought he had a daughter, and asked if she would take her off her bio mum. Mum refused, and it was never brought up again. So, I have no idea if I have a half sister out there or not, and since Dad died 12 months ago I guess I won't ever know.
I wish he hadn't told me, but Dad told me that Mum cheated on him- around the time that my little bro was conceived. Now I can't help but wonder if my little bro was a result of the affair. This is something I don't think I'll ever resolve, bro was the apple of Dad's eye, (only son) and Dad is bro's hero. I think it would break his heart if he knew. (I don't think my younger siblings know).