Did any American President never get married?

1President Bartlet's comments are meant to make him sound erudite, but frequently misfire – in the example cited, for instance, there has never been a king of Liechtenstein (it is a principality, ruled by a prince); the Prince in 1871 was Johannes II, who was unmarried, and had no daughter; and the United States has no ambassador to Liechtenstein (the Ambassador to Switzerland serves Liechtenstein's needs). It is unclear if this is an "intentional" error (intended to show that Bartlet is sometimes mistaken) or an unintentional error on the part of the writers of The West Wing. These "goofs" could be a deliberate policy on the part of the writers, however, to subtly reinforce that the action is not taking place in the "real" U.S., but in a parallel version of it. Bartlet has been shown to occasionally make up things. For example, he cites extremely detailed budget figures off-hand in a meeting, and when asked by Chief of Staff Leo McGarry later Bartlet proclaims in a shocked voice, "I was right?"