My Dad kept us secret from his second family and when it came out, it caused by half siblings great pain that they had been lied to all their lives. It unsettled my late brother a great deal whilst my sister took it in her stride.
I agree with those who suggest you get counselling. You are absolutely within your rights to feel betrayed, cuckolded or any way you wish to word it but it is the way you handle it that is important for your wellbeing. You need help to process this and to assist you to make the decisions of what to do with that information.
Finding out that both your parents lied to you is a huge thing. Please do not let anybody else tell you differently. They may not have meant to inflict damage but they did and you are allowed to grieve.
Morecambe and Wise - the lost tape



