Favoritos de cecileroux

Dear spider experts. Maybe you can help to shed some light on my observation. I found this beautiful female Caerostris with a male sitting tightly next to her. I thought it was just coincidence and that he would become dinner soon. However, two weeks later they were still "cuddling" and sitting in a similar position, once on a different tree connected by the bridge line. When I first saw them, the female had produced one egg-sack, and a second one during my second week of observation. I assume the male is the same one during this time. Then, to satisfy my curiosity, I went on the hunt for more Caerostris spider in the same vicinity. I found six more females!, and two of them had a male sitting next to the female, just like spider no. 1, while one male was sitting between the "horns" on top of the female. I have not yet found a female with more than one male, but will keep observing. My question is whether "mate-pairing" in spiders is common, or am I missing something. Thanks!

Note: I have photographed this Hexatomini at Cedar Bog in Champaign County, Ohio for at least 17 years. Always in the same area.
I've added two other observations; one from back in 2004.
Links to those observations:
https://www.inaturalist.org/observations/88273567
https://www.inaturalist.org/observations/84762884
Here's an observation this year (2022) with better pics of wing venation. Same location.
https://www.inaturalist.org/observations/124010854