Nick Knowles' estranged wife, Jessica Rose Moor, accused the TV star of refusing to pay for the private education of their son, amongst a host of other claims on Twitter
The pair are separated and have been on good terms until the outburst from Jessica.
In the tweet, two images of a noted paragraph of text, Jessica claimed that as well as withdrawing his promise to send their son Eddie to private school. the DIY SOS star subjected her to "intimidation, emotional cruelty, physical abuse and eventually isolation".
The tweet also claimed that Nick Knowles refused to buy a house for Jessica and their son.
She said: "This is disappointing but not unexpected. Some people's generosity is only present in front of TV cameras."
Withdrawing from his promise to pay for their son's education is made worse because Eddie was not submitted for state schools, due to the agreement that he would be privately educated, Jessica alleged.
Jessica ends the tweet: "Since he was born my sole priority has been Eddie’s well being and I felt my silence was in his best interest but now I have to fight, which isn’t in my nature, but I’m fighting for my son. What mother wouldn’t."
The statement comes as a shock compared to how the couple had been together in the past. They have previously separated twice, but always remained on good terms throughout, going on holiday together as recently as December 2017 with their son.
Speaking in November last year, Nick said: "I can’t say enough about Jess. She’s the most amazing mum, she’s the most amazingly calm human being.
"We’re working on our relationship is where we are. Our central point has to be our son Eddie and always has been. He’s a real joy and makes me smile every day."
Nick supported Jessica throughout her cervical cancer diagnosis in July 2016, months after their first split.
A friend of Nick's disputes the claims, telling the Mirror: "I have known Nick for a long time. I don’t think anyone who knows him would ever believe these allegations.
I think Jess is really going to regret this and it’s such a shame because they had such a great relationship. And they always remained friends for the sake of his son, who is the most important person here."