A Brooklyn man apparently decided that three was a crowd he didn’t want any part of.

The 54-year-old man admitted that he used a piece of furniture to beat up a man who he said was sexually assaulting his girlfriend.

But cops tell 1010 WINS, the three people knew each other and had a consensual three-way sexual encounter on Saturday.

When the 54-year-old man returned to his apartment on Sunday, he found his girlfriend getting reacquainted with the new man.

He allegedly flew into a jealous rage and beat the man with the wooden leg of a coffee table.

Charges were pending against the suspect on Monday, as the victim remained hospitalized in critical but stable condition.

The woman was treated for shock.