Liverpool Crown Court was told PC Kenneth Williams kept up a double life for more than nine years, telling a string of lies to his wife, his girlfriend and his police superiors.
But the ceremony he went through with Debbie Wolfenden, a detective constable, in Woolton, Liverpool, on 4 June last year was "the cruellest deception of all", the court heard.
Williams, 35, of Childwall, Liverpool, admitting falsely claiming that he was a bachelor to obtain a marriage certificate and two other deception charges, but denied a charge of attempted bigamy which was left to lie on the file. The court heard the marriage was not registered because of a discrepancy in the wedding licence.
Judge David Clarke QC told him: "This case tends to prove the adage that truth can be stranger than fiction. There have been times when you appear not to have known the difference yourself.
"You lied to Miss Wolfenden repeatedly over a number of years. You gained her trust, her love, her sympathy for you for the personal tragedies you claimed had occurred." The judge said it was remarkable his wife had supported him because his wife and son Stuart, a 12-year-old cystic fibrosis sufferer, were also victims.
Geoffrey Lowe, for the prosecution, said Williams married in March 1979. He and Miss Wolfenden served on the same section at Copperas Hill police station in Liverpool.
By the end of 1982, Williams said his marriage had deteriorated and, by 1984, Miss Wolfenden's friends were aware of a relationship between the couple. Miss Wolfenden decided to end it the following year when she realised he would not leave his wife.
But two years later, Williams told her his wife had a brain tumour and the prognosis was poor. He was given compassionate leave and asked Miss Wolfenden to wait for six months while she recovered.
Mr Lowe said all of this was untrue. In November 1992 he produced a photostat of what he claimed was a decree absolute from his wife. It was a forgery.
"From this point on, Miss Wolfenden thought their relationship was a normal one and was relieved that the pressures she had felt hitherto had disappeared."
Mr Lowe added: "The defendant invented an entirely deceitful family history. Among the other lies, he claimed his mother lived alone and his father was a patient in a mental hospital."
By Christmas 1993, he was leading two lives. "He overcame the difficulty of being in two places on Christmas Day by telling his wife he was involved in investigating a serious case of child abuse. He told Miss Wolfenden a brother in Bournemouth had committed suicide."