Aaron's ex-girlfriend -- who RARELY speaks about the Packers QB -- opened up Wednesday on "Andy Cohen Live" ... and addressed the rumors that SHE was the cause of the rift between Aaron and his parents and brothers.

Remember, there was that famous scene on "The Bachelorette" (starring Aaron's brother, Jordan) when the family had an empty chair at the dinner table to symbolize Aaron's absence.

Munn says the truth is ... Aaron had stopped talking to his family about 8 months before they started dating in 2014 and she was the one who tried to convince him to reconcile!

"On my last day when I was filming 'The Newsroom,' I spent the day in my trailer just encouraging him to, like, have an honest conversation with your parents."

Munn suggested there were jealously issues with Aaron's father and brothers -- who each had dreams of sports success -- and it created a complicated family dynamic.

"I don't think either side of the road is clean," Munn said ... "But, I do think it’s NOT okay when you try to stand on someone’s shoulders and then throw dirt in their face, which is what I think they did with him."

Munn and Rodgers called it quits about a year ago and Olivia says they no longer keep in touch.

Rodgers is now dating Danica Patrick.