Marino reportedly had the affair with Donna Savattere, a then-35-year-old production assistant at CBS Sports where he's been an analyst since 2003.
The affair allegedly took place in 2005, a few months prior to Marino being inducted into the Pro Football Hall of Fame.
The affair spawned a daughter, now 7-year-old Chloe.
Marino paid Savattere millions to keep quiet, according to the report.
According to the report, Marino admitted to the affair in a written statement to the Post:
"This is a personal and private matter. I take full responsibility both personally and financially for my actions now as I did then. We mutually agreed to keep our arrangement private to protect all parties involved."
Marino, famous for being a model father and husband off the field, has been married to his wife Claire for 28 years, and insists his family life is still intact.
"My wife and I have been married for almost 30 years and have six children together," he wrote in the statement.
The report does not say how much Marino gave Savattere, but it was apparently enough for her to move away from New York -- where the CBS Sports studio is located -- to Texas.
Since then, she's returned to Manhattan and been an active part of the social scene, reportedly living large in the Upper West Side as well as the Hamptons.
She often showed her friends photographs of herself with Marino at restaurants and clubs, according to the report.
She has since married and had a child with her husband. Marino has been in contact with Chloe.
According to records, Savattere petitioned to change Chloe's name to Chloe Alexis Younis -- the last name of Savattere's husband, whom she married in 2009.
The Post says Savattere could not be reached for comment.