Yes, what a shocking way to learn he's gay.
And yes you want to detachment from him - there's no point in being angry with him as he is immune to it, it's like giving good money after bad, but this is more to be angry about, not just the sending of the pics but also the new information is unwinding more of the abuse he subjected you to. It's like bruising - the colours rising to the surface express just how bad the bruise was.
I really don't think you can move past the anger. I think it's healthy to feel angry at being so lied to, manipulated and utterly used. And I think it deserves to be listened to.
I have two very different strategies. One is to use the energy to work on something I want to accomplish. And the other is to curl up on my bed, cuddle up and let the feelings come and go, listen to myself.