As frustrating as it is about the MC session, in which you did not do anything wrong, here is my take on handling it...
I think Michelle would say for us to not assume he didn't intend to keep the MC, but rather assume he did. Act AS IF he did at least.
My H was very very fearful about MC being one-sided. Your H I believe knows that you have been working hard and he has been struggling with his own emotions and not knowing how to handle them and doesn't want to hear that he's not handling them well. I believe he is fearful of being criticized. Criticized that he isn't handling "reconciliation" well. Fear that his emotions and reactions will not be validated. And now for him, perhaps, the fact that you went to the MC without him pushes those fears into overdrive.
Your H is being very emotional. All his outbursts, his behavior, his attacking, his defensiveness and offensiveness is out of swimming in these emotions he doesn't know what to do with.
This is a great opportunity to validate. Validation feels a bit weird at first, until you get in the practice. Stop, use a calm voice, think through your words before you speak. You can validate without agreeing. Without defending, without offending.
It doesn't matter what your take is on a subject to validate. You are validating what is reality to him. Not you. So you can validate him by stating that you understand that he feels that now the MC has heard only your version and that he feels the presentation of the situation may not be fairly and objectively presented. You can validate that. That is his fear. You don't need to offer a soln. Just validate that fear. And as the conversation progresses, let him do the talking, make suggestions if he does, whatever.
Concrete goals can be that you will use a calm and non-threatening tone and demeanor. That you stop what you are doing, look at him, listen, pause and think before you speak to validate. That's all you need to do. See what comes from him with this. And if he gets defensive, offensive, or whatever, you do not need to participate by becoming that way yourself. Just validate that you understand what the reality to him is. That's all. See what happens.
