According to the latest BBC article:
Gaiman's representative's previously told Tortoise that "sexual degradation, bondage, domination, sadism and masochism may not be to everyone's taste, but between consenting adults, BDSM is lawful".
i don’t particularly want to rehearse the reported details. They are pretty gross, you can find them online here: https://archive.ph/O1s0J
it is pretty clear that there was a significant age and power disparity. The dispute appears to be around consent, with a significant number of women saying no/no proper consent was given. Role model, hero and feminist he is not, either way.