The accepted definition of a widow is a woman who was married to person at the time of that person's death:

https://legal-dictionary.thefreedictionary.com/widow

(The definition specifies "husband", though I suspect with the rise in gay marriages, a female survivor of an intact legal union will be considered a widow regardless of the deceased spouse's gender.)

There's also the peculiarity of Western (predominantly Christian) tradition to unquestioningly accept serial polygamy, but not simultaneous, despite at least the sexual elements the latter itself being a widespread practice.

I can't speak for notafraudster's intent, though their usage isn't an accepted one.