Angry beau bashes rival in sex shock

THREE MAY have been a crowd for a Brooklyn man who nearly clubbed a rival to death Sunday, after a possible ménage à trois gone bad, police sources said.

The 54-year-old attacker told cops he walked in on another man sexually assaulting his girlfriend in the couple’s secondfloor apartment in East Flatbush at about 6:45 p.m. Sunday, sources said.

The alleged attack took place in an apartment in Camba Gardens on Albany Ave. at Clarkson Ave., an affordable-housing building that replaced a demolished psychiatric facility on the Kings County Hospital campus.

The older man told cops he attacked the other man, 31, to stop the assault, swinging a wooden coffee table leg at him, according to the sources.

Police were investigating the man’s account to determine whether he walked in on a sexual assault or a consensual encounter, the sources said.

Both men may have been involved in a threesome with the woman, 30, on Saturday night, according to sources.

When police arrived Sunday, they found the younger man unconscious, with serious head injuries, cops said.

Medics took him to Kings County Hospital in critical condition. The woman was also hospitalized.

Police took the older man into custody.

Charges pending. against him were