Certain activities cannot be performed alone — such as quarreling, making love, and dancing the tango.
it takes two to tango
The active cooperation of both parties is needed for some enterprises, as in We'll never pass this bill unless both parties work out a compromiseit takes two to tango. This expression dates from the 1920s, when the Latin American tango became a very popular dance. It was popularized by the singer Pearl Bailey in her 1952 hit song of that name written by Al Hoffman and Dick Manning.