Despite having recently chastised Barbara for talking publicly about their marriage breakdown, Becker has revealed very intimate details of what he says were their darkest hours.
Writing in his second autobiography, Becker, 45, admitted he was what he described as, "without doubt the arsehole in this family drama."
"I had been unfaithful to my pregnant wife, fathered a child out of wedlock and hidden the truth for a long time," he said.
But in extracts published exclusively in the Bild tabloid newspaper on Thursday, he said he had betrayed Barbara because he wasn't getting the love and attention he needed from her.
Poor Boris wrote: "I was yearning for love, security and intimacy. And if you do not get that at home, it can happen that you take it elsewhere when the opportunity presents itself."
His desperate search for emotional intimacy led him to a staircase near a broom cupboard in a London restaurant where he had sex with Angela Ermakova and got her pregnant - while pregnant Barbara was at home.
Becker has followed his initial autobiography called The Player with this second one called Life Is Not A Game, to be published on October 2nd.
The first excerpt published on Thursday exposes the back story of what is now presented as a harmonious patchwork family. He and Barbara Becker have two sons Noah and Elias, while he also has contact with Ermakova's daughter Anna - and has another son Amadeus with his second wife Lilly.
He said that after seven years of marriage, he and Barbara had nothing left in common. "We had no common goal, no basis together any more - I don't even want to start to talk about sex and eroticism."
He said the worst chapter of his life was after the Ermakova affair had become public and Barbara had left for Miami with their son Noah and the new baby Elias. His tax affairs were being investigated and Ermakova was insisting that her new baby Anna was his.
"That was - for us [Barbara and he] as a couple and for me as a person, the absolute Waterloo," he wrote. He said once when he was visiting she attacked him. "She yelled at me, suddenly jumped up and started to hit me like she was out of her mind," he wrote.
He said divorce dramas might sound exciting to outsiders, "but for those who are stuck in it, it is not entertaining at all," he said - while offering up the remains of his for public consumption.