Why did Grover Cleveland serve two nonconsecutive terms?

Grover Cleveland (1837–1908) is the only man to serve two nonconsecutive terms in the White House. His two terms (1885–89 and 1893–97) were interrupted because he lost the election of 1888. He was a popular Republican president, especially during his first term.
His loss in the 1888 election was controversial for several reasons. First, Cleveland narrowly won the popular vote but lost the election. His opponent, the Democrat Benjamin Harrison, won in the Electoral College 233 to 168. The most important issue was the tariff. Cleveland wanted a low tariff to benefit consumers. Business interests, on the other hand, wanted a high tariff. Republicans outspent the Democrats and even used paid "floaters" in Indiana. A "floater" was paid to vote for Harrison. Harrison was not personally corrupt, but he benefited from his party's dubious tactics. After one term, Harrison lost badly to Cleveland in the election of 1892.