When he blames you for his relationship with the kids just ignore it. He's still eyebrows deep in affair fog. Everything in his joke of a life will be your fault. He's convincing himself that he's justified in his actions because you're so "horrible". The reality is he's a selfish jackass behaving like an idiot man-child but as long as he's in affair fog he'll never see it. He might have an epiphany at some point and snap out of it. Was he generally a good person up until this point or has he shown at any time in his past that he can be cruel and sleep like a baby at night?