Doubts about hurmate musaaharah

I was sitting and reading Quraan and thoughts about hurmate musaahara came to my mind. I'm really scared to shake my father hands. I don't have no feeling for him but the thought comes now that is my step mums and dads nikah valid? I was sitting and reading Quraan and this thought and image came in my mind that I was young, in my teens probably, and my dad was lying down and he had on a lungi.Probably the lungi was open and I was sitting by the leg side and from the bottom, when he widened his legs I could see the testicals. Does my step mums nikah break with dad? I can't even remember exactly but I'm not even sure if i saw the testicals or penis, but obviously I won't have no lust for him.I don't think there was even lust but I'm just getting these thoughts if dads nikah is valid.