Oh, B, I truly understand. I've been right where you are. I think last night's episode may have triggered your feelings of abandonment. It scary when we lash out and the result is that we push the other person further away. It can make us feel desperate, thinking it's all our fault. B, it's not. It really isn't.
What has helped me a great deal is understanding what anger really is. Learning that it is either fear or pain has enabled me to deal with what I'm really feeling. I have been able to apologize for the anger, but I don't feel bad about the fear or pain that was behind my words. I'm honest about the true feelings and, surprisingly, I don't feel vulnerable. I have been able to look back at times I've been angry and now see what I was really feeling. I can also look at my kids, H and others and see beyond their behavior. It's so much easier to see that the actions are not personal. It's about them.
It seems that your words last night were about the pain you felt when your time with your kids was not be respected and, the greater pain, that OW was spending time with them. It was the four of them when it use to be the four of you. That is so very painful. Please see yourself for who you really are. You are a loving person who is hurting badly. Please find some compassion for yourself.
I want to encourage you to be honest with your H about your anger. Do that for you. I hope you find the relief that I felt when I was in the middle of a heated exchange with my H.