Do you have any ideas about the previous king of deepnest Herrah married and then died?
I consider FPK Herrah to be a lesbian (which funnily enough is more of a "default" situation with Weavers, since in the AU Pharlids were an all-female species), so if she married a male bug then it had to be for a specific reason.
For some AU lore context, since the Weavers fled Pharloom after the rebellion, with most of them dead, they would surely seek ways to rebuild their population and survive.
But their biology was messed up when they were evolved using silk, and so the majority of them were infertile or had other issues connected to it. Pharlids reproduced predominantly asexually (sexual reproduction was a possibility and it resulted in some hybridization between species), and the forced evolution affected that ability of the Weavers, making self-fertilization, even with the help of their simulated mating that increased the odds of fertilization, practically impossible. This left mating with male individuals of other species as the only chance of having children.
Perhaps Herrah's marriage to the bug wasn't just a way to secure a new home in Deepnest for the Weavers, but also an attempt to have offspring and to repopulate her clan, which is kind of sad to think about considering she was a lesbian. Maybe it was an expectation that was put on her because she was physically the strongest, and so would be able to carry the offspring to term - another reproductive issue the Weavers faced was that, if conception with a male individual occurred, the majority of offspring died before they could hatch.
Regardless, they were not successful when they tried, and her husband unfortunately died not long after they married. This left the Weavers of Deepnest in a dire situation, and so when the possibility of having a child with the king of Hallownest appeared, she took it without much hesitation.
I do think she genuinely did want to have children, it wasn't just something she was expected to. I think despite her title and her intimidating appearance, Herrah was a very loving and sweet individual, and she would be an incredible mother if things went a different way.
As for her dead husband, I haven't thought much about what he would be like. I know he would be the leader of the settlement in Deepnest, and agreed to let the Weavers live there if Herrah married him (perhaps he was also looking for a suitable mate). Personality wise, I'm not sure what he would be like, but I know there were no romantic feelings between him or Herrah. Did he know about her feelings for Vespa? Likely not, especially since he didn't live for long after marrying Herrah. How did he die? I don't think Herrah had anything to do with it, it seems out of character for how I imagine her. So perhaps it was an illness of some kind, or he died from injuries. I'm not sure. And I'm not sure how much thought I'll put into his character considering how minor of a role he has.