first of all my heart goes out to you and your son
It may be very difficult for your son when he does learn how it was he was brought into the world. I had a friend who was brought into the world in a bad way such as this and she was always at odds with who she was and why she was.

Please go very gentle with yourself and just focus on being the best mommy you can be to that innocent life. Both of you were innocent victims of a coward and thief.
Allow your husband to be the good safe arms around you that you need.
And know fully that all the pain you have and the emotions (even the secret stuff you can not tell anyone) that it is all valid.

Welcome to PC and I hope you find on here friends who care and can understand and will be there for you.