If you're confused and worried, try to imagine how it is for your son. Someone said they can't imagine being straight would be easier... yeah, it is. And in the ups and downs, your son is going to be happy knowing he was truthful with himself before being truthful with anyone else.

The only reason it's so shocking for parents to hear their children are gay, bi, pan, etc, is because being straight is seen as the "norm" and any sexual minority is seen as "obscure".

To be shocked because you're worried is of a different nature. If you feel as though his father or step father may harm him if they find out (and I don't mean just physically) you need to work to protect your son. Children come first, especially in cases like this.

I agree with what others are saying. Definitely speak to him about sexual health (as gay relationships and sexual relationships are not spoken about in sex ed within schools), let him know that he can come to you with anything, and most of all show acceptance and care for him, because as you already know and I can see you're doing it already, he's still your son and he still needs his mom. And you'll do great.