A high-response police driver ignored emergency calls while having sex at his lover's house, a court heard.
Tim Reid, 41, of Widnes, Cheshire, even failed to respond to a call about a man who threatened to throw a petrol bomb.
Judge Adrian Smith at Minshull Street Crown Court told the married father he was guilty of "complete foolishness".
The former Cheshire officer, who admitted misconduct in a public office and disclosing information, received a nine-month suspended sentence.
The court heard that Reid began an affair with Michelle Harper, whom he met when he was called out to an incident over a firearm and arrested her boyfriend.
Two months later he gave her his mobile phone number which led to him sending 216 flirtatious text messages to her while on duty.
Despite this, his wife was in the court and was standing by him and the pair were attempting to move on, Debra Whyte, defending said.
Julian Hayhoe, prosecuting, said one of the texts sent to his lover read: "I fancied you from the start. Your eyes light up and have a naughty glint in them. I cannot believe I have entered a naughty relationship with a witness but I do not regret a thing."
Reid said he had sex with her on up to six occasions at her house while he parked his marked car outside.
The officer also discussed with her the ongoing proceedings of her boyfriend's arrest, criminals he had dealt with and details of imminent arrests, the prosecutor said.
The relationship came to light when a neighbour noticed Reid's car had been parked nearby at regular intervals during the day.
Even when the police started to investigate, Reid continued his affair for another month as he told Miss Harper to deny to officers that they ever slept together while he was on duty.
Ms Whyte said that, prior to his conviction, Reid was held in "high regard" by his employers.
She said: "This defendant regrets enormously the way in which he has conducted himself.
"He acknowledges that this was a breach of trust. He acknowledges he has abused his position."
She added that Reid had found new employment and had an offer of another job but that would be lost if he was sent to immediate custody.
Sentencing, Judge Smith told Reid: "These offences represented a complete foolishness in what otherwise was a long and distinguished career as a police officer.
"This course of conduct has had a far-reaching effect on you and your long-suffering wife. You are extremely lucky that she is standing by you. You look suitably ashamed by what you have done."