funeral rituals

At the end of Enchi's The Waiting Years, the main character asks to be dumped at sea. What would this mean in Japanese culture?

I haven't read this novel ("Onnazaka" in Japanese), but in Japan, when you die you are typically cremated and your precious ashes and bones would be buried in the family grave. The family grave is where all the bones and spirits of your late family members and ancesters rest. If you are a married woman, that grave would typically be your husband's family grave.

Nowadays, cremation has become a legal must due to sanitary reasons , while burials have become more free and there are many people who have their ashes scatered to the sea, or many would obtain a new grave if you don't want to rest with your husband or your in-laws. But one can assume that in the era of the novel, which was Meiji, burials and beliefs were more conservative, while people may have had the lawful freedom to not be cremated.

Guessing from the synopsis, it is natural to assume that the female character didn't want to rest with anyone else nor have anything to do with conservative rituals. But the husband seems to think that unless great funerals are given, it would be a social embarrassment for the family of the deceased. Or perhaps he simply believed that the wife won't rest in peace unless he does the rituals properly.