The man, only named as Jan, married Monica, his family's former au pair in a previous marriage, in 1993 despite legal difficulties raised by the Belgian immigration authorities.
But it was only in recent weeks that he discovered that his wife had originally been a man and had undergone a sex change.
"I feel I've been assaulted," he told the Het Nieuwsblad newspaper.
"I brought her to Belgium. That was not easy. The Belgian courts had serious doubts about the authenticity of her birth and her identity papers, but eventually they accepted it anyway. I thought she was an attractive woman, all woman. She had no male traits."
Jan, 64, said that he and his wife had decided not to have children because he had two by his previous marriage and she fooled him by pretending to menstruate, using sanitary towels, "to conceal the truth".
"Even during sex, I never noticed anything," he said.
For many years the couple lived a normal family life and Monica, 48, was like a "big sister" to his children until their marriage started to come under strain when she got a new full-time job.
"Monica began to change very much," he said.
"My oldest son saw her sometimes at a nightclub. She began to wear very flashy clothes, those ultra-short skirts or tiny tops, so her abdomen was completely exposed."
Finally rumours began to surface and after Jan found "amorous messages" from other men on her computer, he confronted her in a violent row that led to the police being called.
"A friend told me that he had heard that Monica was actually a sex-changed man. I could not believe it. My son heard similar rumours," he said.
"I pushed her against the wall and said: Now I know the truth. Are you a man? She then announced that she was born as a boy and that she had been operated on. She was now a woman, and so she did not need to tell me about her past as a man. My world collapsed. That evening came to blows. The police came."
Jan, who is undergoing psychiatric treatment following the discovery, has started legal proceedings to have the marriage annulled but the Belgian courts have so far refused to allow him to turn her out of the familiy home.
"That person has deliberately deceived him for years, even scammed. Presumably she has also forged documents used here to get a residence permit. The children, who for years have lived with her, are devastated," said his Liliane Verjauw, his lawyer.
Belgian discovers his wife used to be a man after 19 years - Telegraph
19 years of one huge L 