1. it takes two people to make sth happen
it takes two to tango
The ‘tango’ is a dance for a female and male dancer that comes from Argentina. The idiom ‘it takes two to tango’ implies that the particular task in question requires two people to be involved - and that one person could not have managed it alone. It can be used as a way of suggesting two parties are linked in some way or that they are equally responsible. Usually, this phrase is used where there is a negative connotation.