
He came to tell you directly. That’s something at least. Tell him you still want him in your life if that’s true. If he’s been there since you were 10 and been a good step father to you, I have little doubt he cares for you and will want to continue being a part of your life, even if that’s in a reduced capacity
I'm sorry that's really rough, as another person said, he came to you directly which means he respects you and wants you to hear what's going on from him. Let him know that you respect him and love him and want to figure out what's going on and keep in touch with him!! You will get through this, unfortunately the only way out is through a lot of the time but you can do it!!!