Most modern First Ladies have been politically oriented and have campaigned for their husbands, so they are in the limelight, but they almost seem to get smeared more than their husbands.
Eleanor Roosevelt was viciously mocked for her appearance and height by FDR's detractors. Patricia Nixon was attacked by Richard Nixon's critics for appearing superficial. Nancy Reagan was attacked for getting the White House a full-service chinaware set for state dinners despite the fact she used private donations to fund it, and for her alleged belief in astrology. And Michelle Obama was attacked because she allegedly didn't look feminine enough for some people's tastes.
Melania Trump is the least political First Lady we've had in decades, but she was attacked for the remarkably common sense, IMO, choice to remain in New York City so that Melania's and Donald's son Barron could finish out his school year before transferring to a Washington DC private school, and she is attacked for being beautiful.