answer:Don’t pretend, it is dishonest to yourself. You can be honest and straight forward to your cousins without expressing untoward language. If the question arises, just mention that your bio-dad has never taken an interest in your life and it hurts. That’s all you have to say, but don’t let it be a secret that will fester in your own psyche. Get the truth out without animosity or anger, just let them know. I know this is not easy, but it is not your fault. But people don’t get a pass for this kind of stuff, especially if they are aware of the backstory. Be honest with yourself and take care of yourself.