Neither Duchess Camilla or Kate will ever be Queen, They are not in the blood line. Prince William or Prince Charles can be crowned kings because they are in the Blood line.
The wife of a crowned King (with rare exceptions, although one may be operative in Camilla’s case), the wife of a crowned King is the Queen. Upon the king’s death, she relinquishes her title as Queen and becomes Queen Mother.
The husband of a crowned Queen, on the other hand, is not King, unless he happened to be King of another country.
The crowned Queen’s husband is her Consort, and she may bestow other titles on his if she chooses.