Hi I need some advice. I recently found out I have a younger sister. Basically when i was 4/5 mum had an affair and had another child. She gave the baby up for adoption and her and dad stayed together. My parents both died in the last five years and the ‘baby’ has found me on social media after getting her adoption details. We are both in our fifties and have messaged and met up once. Shes great and we are getting to know each other. Because both my parents are dead and we don’t know who her dad is there’s not really any one we can talk to about this and get more information. I don’t know if my grandparents knew but they are all dead and my uncle didn’t know. I recently told my oldest friend and it turns out she knew and has known for over thirty years (her cousin was close friends with my mum) I feel really betrayed by my friend as had I have known early I could have asked my mum/ dad or her cousin about it but now there’s no one to ask. (Her cousin died 3 years ago)I’ve known my friend since we were children and we have been close our entire lives. Am I right to feel betrayed by her? I don’t know if I can forgive her.