"She said, 'I've had it. I can't do this. I want my life back,' " her sister, Nancy Anania, tells PEOPLE in the latest cover story. Last December, Elizabeth met the 23-month-old Frances Quinn Hunter – the baby John fathered with mistress Rielle Hunter – in a mediated visit at a North Carolina hotel.
The couple now occupy separate residences; she in their Chapel Hill mansion, while he divides time between an annex they call "the barn" and their beach house 160 miles away. Elizabeth, who is still undergoing cancer treatment, has had divorce papers at the ready for a year. Whether or not she files likely depends on her health, a source says.
For more of the Edwards drama, pick up the latest issue of PEOPLE, on newsstands Friday