Oprah Winfrey’s booze and drug binges have finally poisoned her relationship with Stedman Graham.

The ENQUIRER has learned that Stedman, 58, walked out on 55-year-old Oprah for good, and now she’s so worried he’ll spill her secrets that she’s ready to cough up $150 million to buy his silence, insiders say. 

Not only that, sources say the once-invincible media mogul is struggling to overcome a moun­tain of personal and professional headaches. 

“Oprah has not been THIS unhappy in a long time!” a close source divulged. 

“She’s trying to hold herself together, but every day it seems like she gets hit with a new problem, and her world is collapsing around her. 

“During their final blowup, Stedman told her she needed help, but Oprah told him he was seeing a problem that wasn’t there. 

“Right now she’s in panic mode.

"She’s fearful Stedman could write a book and tell ALL her secrets. Oprah feels she needs to buy his silence and is willing to pay him $150 million!"

For the full story with all the deets on Oprah’s wild parties with pals and how she’s now drowning in her OWN sorrow — pick up the new ENQUIRER – on sale now!