And he only came clean about sending porn to a teenager after he was confronted by National leader Judith Collins - despite being investigated by police.
Collins yesterday condemned Falloon, calling him "a liar" and saying it had become apparent his actions were a "pattern of behaviour" with three more women coming forward yesterday to say they'd also received explicit images.
Falloon's political career began to unravel on June 30 when he sent a pornographic image - not of himself - to a university student. Police investigated but decided the matter didn't meet the threshold for prosecution.
The teen's parents then emailed Prime Minister Jacinda Ardern's office on Wednesday, which sought permission to pass the matter onto Collins.
The Herald understands Collins' chief of staff was emailed about the incident on Friday afternoon and Collins was told herself at 11.30am on Saturday.
The leader called him that day to discuss the allegations and summoned him to a meeting first thing on Monday morning to put it to him in person.
Collins said she asked Falloon on Monday whether there was anything else they should know about.
"We were told 'no'. That's an enormous lie and one that goes to the heart of whether or not I could trust him as an MP and so he's gone."
Falloon announced he wouldn't stand again in his Rangitata seat at the election but resigned immediately yesterday after Collins called for him to do so live on radio, and TV.
It was clear his actions were a "pattern of behaviour", said Collins, with two more women contacting her office on Tuesday morning and another speaking to media.
"He's been lying and that's the problem. The one thing about liars is you never actually know that they're lying until you've got the information otherwise.
"If someone tells me quite firmly, 'these are the facts' then I am obliged - unless they have contrary information - to accept that."
The allegations have been referred to police who have reopened their case and are seeking more information.
Collins defended her first statement about Falloon's resignation, citing mental health concerns because there was a genuine worry about his safety.
"We will always remember that Andrew Falloon, although no longer an MP for the National Party, is still a human being and he has a family," she said.
"If someone's sitting in my office and telling me they have a serious mental health condition for which they've been receiving treatment, I will take it seriously."
After his Monday meeting, Falloon was escorted to the airport and was picked up in Ashburton and driven home to his family by the party's mental health spokesman Matt Doocey.
Collins said she'd made it clear to her caucus about her and New Zealanders' expectations of them and gave them the opportunity to come forward if they had any more information.
"I was very, very clear as to my expectations. I told them to accept the privilege of being an MP and that I expect them to act in a professional manner that this is not the sort of thing that people expect from their MPs or anyone else in a privileged position."
Falloon's parents yesterday said they were "shattered" over their son's sex-text scandal and are yet to speak to him.
John Falloon told the Herald he only knew what was being reported in the media.
"He's not well at the moment and we're just seeing him through that."
John Falloon was confident that his son was getting appropriate support.
"We're just trying to keep him protected at the moment," he added.
"It's been pretty shattering. But life has these wee surprises."
