Two’s company, three’s a crowd

Definition

The idiom “Two’s company, three’s a crowd” is a phrase used to describe a situation where two people are comfortable with each other, but when a third person enters the mix, it makes the situation uncomfortable.

Examples

When I asked my two best friends to go to the movies with me, they said two’s company, three’s a crowd

My parents always said two’s company, three’s a crowd when I wanted to invite someone over to hang out.

Origin

The origin of this phrase is unknown, but it is thought to have been in use since the early 19th century.