The British rocker dropped out of a full reunion of the band's original line-up alongside Ozzy Osbourne, Geezer Butler, and Tony Iommi in 2012, saying he wanted a "signable contract" that "reflects some dignity and respect toward me as an original member of the band".
As a result Ward was not involved when the group released its latest album 13 in 2013, and he has engaged in an increasingly bitter war of words with frontman Osbourne ever since.
Now the percussionist has revealed he blames Osbourne's wife Sharon for the falling out, insisting she has a personal dislike of him which resulted in the contract offer he felt was unfair.
Ward tells the Eddie Trunk podcast, "I know that Sharon definitely dislikes me, and she has for a long, long time. And I also know that she is inside all these contractual things, these unsignable contracts and everything else. She's right there, right in the centre of everything - as are the other lawyers as well, the other representatives. But, you know, the statements were made by Ozzy. It's broken up the friendship that we had. There's no doubt about it. I mean, it f**king killed the friendship."