I was thinking mb28. If your H books another appointment and does NOT file for D on Monday ( I suspect he won't ) then when he is THERE... THANK him solemnly for going to his IC session and quietly slip your ring on...

Don't SAY anything, keep it subtle.

I remember you said you had taken it off... thanking him for the IC VERY calmly and silently slipping on your ring would be a good moment that they might notice.

Don't get into a convo aftewards, if he says anything...

Just tell him its time for him to go home, you don't want to fight.