The wife of the King can be Queen (although not this time, due to past scandals). But the husband of a Queen cannot be King. I see it as a holdover from medieval patriarchal thinking. A King can have a Queen, and that's fine. But a Queen cannot have a King, because that would mean he outranked her.That's nice.
The King is 'His Majesty' now, his wife whoever she was is Queen Consort as she's not Queen in her own right, it's a fancy way of saying she's married to the king. She's addressed as Your Majesty, and will be crowned alongside Charles in May.
William and Catherine formerly the Duke and Duchess of Cambridge are now the Prince and Princess of Wales.