Former Boyz II Men bass singer Michael McCary made R&B history throughout the ’80s and ’90s before mysteriously splitting from the group in 2003. Now, the artist says the reason he left the band is that he suffers from multiple sclerosis (MS), an illness he’s had since his early twenties and that led to chronic back trouble, depression and the end of his music career, The Huffington Post reports.

During an appearance on the reality TV show Iyanla: Fix My Life, McCary said he’d felt abandoned and betrayed by his band mates after years of struggling with his health. That’s when he revealed he’s been living with MS for decades.

Multiple sclerosis is an autoimmune condition that affects the central nervous system and disrupts the flow of information throughout the body. The disease slowly damages the protective coverings that wrap around nerve fibers in the brain and spinal cord. This results in a wide range of symptoms that include muscle spasms or weakness, vision problems, difficulties with coordination and depression. There is no known cure for MS and current treatments are only modestly effective.

“It was like little back spasms at first, and then they would get stronger and stronger. Each time it would get more harsh,” McCary said. “Once I was about 22, it started going to full-scale.”

But McCary kept his condition a secret and eventually left the group. The singer said that once his MS diagnosis came to light, the other band members deserted him. (In interviews they’ve done, his band mates offer other explanations about what caused their estrangement from McCary.)

During McCary’s TV interview with Vanzant, the bass singer said he wanted to get over his feelings of being hurt and abandoned by the group he’d been with for so long and to whom he’d given his life.

Vanzant’s program airs Saturday nights at 9 p.m., ET, on OWN. The show will follow McCary’s efforts to heal and possibly reconcile with his former singing partners while dealing with his illness.

Click here to learn more about multiple sclerosis.