The man, named Jan, married Monica in 1993 despite legal difficulties raised by the Belgian immigration authorities, the Telegraph reported.
But it was only recently that he discovered that his 48-year-old wife had originally been a man.
"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," the Telegraph quoted him as saying.
Jan said 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 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," Jan 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," he said.
Jan found "amorous messages" from other men on her computer. He confronted her and a row ensued that led to 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.
Jan is undergoing psychiatric treatment following the discovery. He has also started legal proceedings to have the marriage annulled.