You will just have to let him vent his anger and whatever emotions he's feeling right now. Each betrayed spouse will have to go through these emotions or healing will not really occur. He has to mourn the betrayal of trust. For now, you will have to take each hurtful word he's going to say because in his mind, it's payback time.
The above is from the point of view of a BS, I went through the same feelings. I was angry, sad, crazy?, and desperate the first few weeks. After that, I tried to find answers, suggestions and support from others including this forum. I still get angry and mad sometimes but not like before. He will get through this with your support. A lot of people here would wish that their spouse is doing what you're doing now.