They spent their lives helping others with problems but a Brooklyn couple who hosted a self-help radio show committed suicide by suffocating themselves with helium and plastic bags. Leaving behind tragic suicide notes detailing a battle with bipolar disorder, police sources and witnesses said, friends and neighbors were taken aback by the tragic and ironic turn of events.

Psychotherapist Lynne Rosen, 46, and her motivational-speaker husband John Littig, 48 — who appeared on WBAI-FM’s “The Pursuit of Happiness”— rigged tubes to a helium tank then tied plastic bags around their heads at their Park Slope home, the sources said.

“I can’t take it anymore, my wife is so sick. She’s in too much pain. Please bury us together,” Littig wrote, according to a building manager who discovered the couple dead.