The 1990s and early-2000s boyband have reunited for the upcoming ITV2 special The Big Reunion, to be broadcast later this month.
Created by Simon Cowell, the group scored several number one hits in the UK, but they have revealed that things were not always rosy behind the scenes.
"On stage we were the best ever, off stage we were a train wreck," Scott Robinson said. "Life in 5ive was mental. It was five years of very hard work. You see the inside of a hotel room, an airport, a radio studio, it's hard."
Abs said: "I know there were times when one of them would be pissed off with another one [in the band]. There'd be fights going off."
Ritchie Neville agreed, saying: "We were difficult, bordering on being arseholes. We were delinquents."
Sean Conlon added: "But like Simon Cowell said, he wanted a band with edge and that's what he got!"
[5ive's current line-up without J Brown]
By the time 5ive had reached their peak fame in the late 1990s, Sean Conlon had to leave the group after suffering a breakdown.
He explained: "I remember looking in the mirror and thinking to myself, 'Who is that?' I didn't know myself and I just had the strongest feeling that no matter what happens no matter how much money they throw at me I've got to find Sean. Otherwise I make thousands of pounds but I'd be spending it all on therapy."
Neville stated that he realised the band was over when he saw Robinson looking "inconsolable".
He said: "We were in this hotel and Scott just broke down, he was crying his eyes out. J and I walked out to him and put our arms around him and he said, 'I just can't do it anymore'.
"I remember looking at Jay and he just looked at me and just went, 'It's done isn't it?' And I went, 'I think it is.'."
Robinson added: "I just wanted a week off from being Scott from 5ive. I was on the edge. We quit at our peak, we were number one at the time and we jumped ship."
[5ive with a reunited Atomic Kitten]
However, Abs revealed that he struggled to deal with the end of the band, saying: "I don't know what the details were, why Scott had to do what he did exactly, because to be honest with you I just felt a little bit like you're taking something away from me."
5ive will appear on The Big Reunion as a four-piece, as Jason 'J' Brown turned down the chance to return.
Scott Robinson said: "I was annoyed with J when he said he didn't want to be a part of this. I was really angry because I've personally myself been trying to get this band back together for years and years and someone's let it down. He will be missed."
Abs added: "I don't want him to regret because it could be something amazing."
5ive were recently reported to be looking for a new fifth member of the band via a Facebook advert.
The Big Reunion launches on January 31 on ITV2, and will also feature the likes of Atomic Kitten, B*Witched and 911.
Watch the video for 5ive's 'Everybody Get Up' below: