Mama, I also sincerely doubt that your H is going to MC with the goal of repairing the marriage. As such, I don't believe that joint counseling will be effective. It may be good to have one joint session today, so that the MC can get a picture of how the two of you relate to each other and see some of the issues involved, but I absolutely agree with OT that you need to see him separately after today.
The LORD is near to all who call on him, to all who call on him in truth." (Psalm 145:18)