Don't go rescue him, BUT you might walk in to the room and calmly state this "Your reaction to my request for information was completely disproportionate to the request. It makes me feel that you are not telling me something, perhaps because you are afraid of how I might react. I can deal with the truth, but I cannot deal with secrets or lies, is there anything you haven't told me? I cannot promise I won't get angry, but I can deal with the truth."
If he doesn't respond then say something like "Ok, no response...I will ask you this again in our next MC session at that time I expect a completely honest answer or access to what I've asked for. If you aren't hiding anything then there's no reason for you to not give me access....I am not budging on this issue, I have a right to view our bills."
He's not going to like it, he's likely to throw another deflection fit. Just walk away...let him stew in it. Just calmly walk away.
Does that mean you stop being his wife? No, you are calmly stating what you require. Now, if he doesn't give you the the truth as to what he's holding back...and/or doesn't give you access to what you've asked for. THEN it's time to rethink some other things...but lets not rush into those things yet. I'm thinking that if you stand firm on this for a few days and let the logic stew...he may come around. You may not like what you hear, but he may come around.
Sorry you are having to deal with this, but perhaps it's a good thing that he's behaving this way now. This will reinforce what you and your MC talked about with "trust".
