Nintendo has officially made Bowsette non-canon.
Last year, Nintendo announced that the Switch version of Super Mario Bros. U would feature a new item, the Super Crown, that turns Toadette into a Princess Peach-esque character called Peachette. Fans ran wild with this idea, imagining it on other Mario characters. In particular, fans became obsessed with the idea of Bowser wearing the Super Crown, turning him into a sexy princess in fetish gear.
According to the website for New Super Mario Bros. U Deluxe, only Toadette can wear the Super Crown (via ResetEra), making all imaginings of other characters wearing the Super Crown officially not approved by Nintendo. The description inexplicably apologizes to Luigi, which is a whole new layer of trolling Bowsette fans.
Don’t despair, though—the purpose of fandom is to explore non-canonical ideas, like what would happen if Bowser suddenly turned into your large wife.