Telling my kids was the single worst moment of my life. But, once it was over we started on our new lives. We are proving to our kids everyday how much we love them. They seem to be doing well.
My only advice is to try to be honest with your son. He knows something is wrong. If you aren't honest about the relationship he isn't going to trust you later on. I would work with your H to build a plan to tell him. There are some good books about how to do this right.
I am sorry about this part of your life. I know as a parent we spend every day trying to protect our kids. Sometimes telling the truth hurts for a short time. Lying hurts a lot longer.
