When Prince Philip married Princess Elizabeth in November 1947 (she was a princess at the time), he dropped his title – Prince Philip of Greece and Denmark and got a new one, Duke of Edinburgh. After Elizabeth’s father died in 1952, Philip didn’t become a King. Elizabeth became the Queen, and there is a reason why.
In the UK, the husband of the current queen on the throne is called a prince consort, no matter the circumstances. The government doesn’t allow foreigners to be king consorts, they are instead given the title prince consort. This happened to Queen Victoria, who ruled from 1837 to 1901 when she wanted to title her husband Albert as king consort, but she wasn’t allowed to because of his origins. It wasn’t until 1957 that the titles weren’t given to husbands of reigning Queen when Queen Elizabeth II decided to name Philip as the Prince of UK. The titles are just symbolic.
On the other hand, when a woman marries a monarch, she usually gets the title queen but is also only symbolic. Elizabeth Angela Marguerite Bowes-Lyon, the Queen Mother, became queen consort when George VI became king, and the same rule will apply to Kate Middleton, who will also earn the title when Prince William becomes king.
However, there will be an exception to this rule, as Clarence House revealed after their wedding that his wife, Camilla, will be known as princess consort, saying, “It is intended that Mrs. Parker Bowles should use the title HRH The Princess Consort when The Prince of Wales accedes to The Throne.” But, Charles can choose to title Camilla as queen consort if he wants when he becomes King.
Another thing worth mentioning is if Prince Philip outlives his wife and their son Charles becomes king, he will be given the title king father like the one Queen Mother had when Elizabeth II came to her reign.
Source: Popsugar