A MILLIONAIRE Sydney businessman who met his wife at a lap dancing club has argued he shouldn't have to pay her a slice of his fortune because she is a gold digger who used frequent high-quality sex to lure him into a loveless and childless marriage.

The 58-year-old claimed in the Family Court he became infatuated with the dancer, who was 14 years younger than him, when they met in 1998.

He claimed that when they discussed marriage many years later he was "emotionally or pathologically dependent" on her, and she used this as leverage to force him to sign away $3.25 million of his $17 million fortune to her in a pre-nuptial agreement.

Once they were married he claimed the quality and quantity of the "intimate relations" they enjoyed before marriage declined steeply.

He believed she didn't love him or want to have children with him. They separated after just two years of marriage.

Family Court judge Robert Benjamin ruled the husband had failed to prove his claims that he had been unfairly coerced into the pre-nup by a manipulative lover.

Justice Benjamin found the wife's claim that the sex did not change much after marriage, and that she did love her husband was more believable.

"(A) change in the nature of intimacy between parties when they marry is not an indication of fraud, coercion or unconscionable conduct. It is indicative of normal human behaviour," Justice Benjamin said.

"These parties were not in the 'first blush' of their relationship in 2005, they had commenced living together about eight years previously."

The wife has been awarded the $3.25 million she is owed under the pre-nup.

Since separation in 2007 she has been living on a wage of $411 a week as she has no qualifications, having left school before Year 10. She has been living in a rented house in Sydney with her de facto partner, a truck driver.

The court heard the husband "found" the truck driver visiting his wife at their $7 million home a month before they separated in May 2007.

The millionaire businessman met the lap dancer when he was separated from his first wife, to whom he paid $7 million in a divorce settlement.

They lived together in a de facto relationship for seven years before marrying in 2005.

Justice Benjamin said the husband had failed to prove he was a victim of fraud and also found it was the husband's idea to have a pre-nup.

The husband tried to demean his wife and her work as a lap dancer during the court hearing, the judge found.

The husband gave evidence that she only deserved a "modest" divorce payout because her contribution to the marriage was minimal.