The comedienne, who is currently promoting her sixth book, revealed that a lot of her anger issues led to her failed relationships — perhaps including her infamous fallout from her former best friend, Jennifer Aniston.
"I'm a great friend, but if you piss me off, you're out," Handler, 44, told Stern. "I was so angry for a long time, and didn't know why."
She admitted problematic "patterns of behavior" led her to seek help from a therapist, who taught her that the constant rage stemmed from her brother's death when she was just 9 years old.
Handler began sobbing to Stern as she recalled the horrific tragedy. (The comic's brother Chet fell of a cliff during a 1984 hiking trip, and succumbed to his injuries.)
"He looked me in the eye and said, 'I will never leave you,'" she recalled as she cried. "I was the youngest, he was the oldest. There was six of us. We were a team."
"My life from that moment on was about not believing anyone ever again because you could never rely on a person ever again."
“I have a very out-of-sight, out-of-mind attitude when it comes to people,” Handler quoted herself telling a therapist. “It seems harsh, but I really just stop thinking about people once a relationship has been severed.”
But it seems the two have reconciled following Handler's therapy sessions.
A source recently revealed to RadarOnline.com that the two have "moved past it, and are friends again."