I wouldn't condone my sons eating high sugar sweets before meals either. I probably would be more lenient if kid had been sick. Couples make such a big deal over little unimportant stuff, though you were wise to realise this wasn't about the marshmallow... .... unless of course H has a fear of the marshmallow man from ghost busters. That could even explain the hoe!!
I see a lot of reconnecting happening. Albeit indirect through humour, he does seem to be trying more and more. I doubt it is a conscious decision on his part, but he does seem to prefer to have improved interactions.
Thank you for giving us this on going observation of his behaviour.
I am glad you are able to step back and not get sucked into reacting and escalating these situations. Well done.
Best wishes
R 25 years M 14 years S11 & S13 Working on it alone since Oct 2014 M in trouble a lot earlier (~2 years) Feb 2016. 1st R chat in a yr. Next R chat Aug'17 Still together