Forgive me if I’m wrong, but this almost seems like you’re trying to convince yourself: “I didn’t do anything wrong – did I?” My father asked me the same question. Nothing he did or left undone made me gay or would have made me otherwise. Instead of beating yourself up for this, instead congratulate yourself and his mother for having brought him up, with the confidence and self-belief to be who he is and with the faith in you for him to be able to tell you. Of the many unpleasant alternatives, imagine instead he had felt compelled to lie, or self harm, or run away, or remain closeted and miserable. IMO you did nothing wrong.