The musician's marriage hit the rocks after his alleged affair with 20-year-old Russian Ekaterina Ivanova and his continuing problems with alcohol.
Wood was photographed drinking with snooker player Ronnie O'Sullivan and artist Damien Hirst days after leaving rehab, convincing Jo that their 23-year union was over.
A friend of Jo told The Sun: "To say she has her suspicions about his drinking would be an understatement. Nothing surprises her with Ron anymore.
"He's moved back from rehab and his family are sure he is back on vodka. They know him better than anyone else.
"One of his sons was told that Ron had been spotted drinking neat vodka again. Jo knows better than anyone that he is an expert at keeping his drinking under the radar."