Henry was absent because he wanted the most important person present to be his son, not himself.

It's not something I'd heard of before and I will try and find a better source if I don't fall asleep first.

http://www.radiotimes.com/news/2015-01-10/lucy-worsley-the-fuss-over-prince-george-was-nothing-compared-to-the-uproar-over-henry-viiis-son