Tory Neil Parish is quitting his role as MP after admitting he "deliberately" looked at pornography in Parliament.
The 65-year-old revealed that he accidentally looked at porn in the House of Commons on the first occasion after looking at tractors online.
But the Tiverton and Honiton MP said the second time was "deliberate" in a "moment of madness".
In an interview with the BBC, he said: "I was not proud of what I was doing."
A tearful Parish later told the broadcaster: "The situation was that - funnily enough it was tractors I was looking at.
"I did get into another website that had a very similar name and I watched it for a bit which I shouldn't have done...."
Mr Parish, who is a farmer by trade, was yesterday suspended by the party after two fellow Tory MPs complained to the chief whip about his behaviour.
He referred himself to Parliament's Standards Commissioner, but as recently as last night had vowed to remain an MP and as chair of the Environment committee while an investigation was underway.
He's now expected to officially "move the writ" to give up his seat when Parliament returns next week, triggering a by-election in his Devon constituency.
He will become the second Tory MP to quit this week, after Imran Ahmed Khan resigned as the MP for Wakefield, after being found guilty of sexually assaulting a 15-year-old boy.
Mr Khan submitted his resignation on Monday and that it was effective from 30 April, meaning he will be paid his full April salary.
Mr Parish said last night that he had looked at something "in error", but wouldn't give further details.
He later said he had made "a complete mistake, and I will man up to it as they say".
And he said his wife had "married a f****** idiot."
