The former husband of singer Britney Spears has said he could have done more to help her when she had a well publicised meltdown following their divorce in 2007.
Speaking to American publication US Weekly, the former backing dancer spoke about his romance and short-lived marriage to the singer. The pair have two sons together - Sean (9) and Jayden (8).
Federline (37) said the couple are on good terms now.
During their whirlwind romance and marriage in 2005, Federline said he saw a "few things go down" but will never discuss what happened out of respect for his former wife.
The pair met shortly after Britney (33) split from her long term love Justin Timberlake.
"We had an instant chemistry – and then it became a soap opera for the world. It surprised me how down-to-earth she was, with normal Southern values instilled by her parents – but also, obviously, not that innocent… I have so many great memories that outweigh the bad," the dancer said when asked about what first attracted him to the 'Hit Me Baby One More Time' singer.
During the interview, he admitted that his relationship with Britney led to a change in fortune for him and he "soaked up as much of the lifestyle" as he could.
"Having 50 paparazzi suddenly in my face was a huge eye-opener.
"Our life was running at 150,000 miles per hour. I soaked up as much of the lifestyle as I could. I’d walk into a club and get a table worth $15,000 a night with unlimited free drinking.
"To not have to worry about making my next car payment felt like a huge weight lifted off my soul. But everything got so crazy," he said.
The couple visited Ireland during their engagement in 2004 while Britney was on tour. The loved up couple got matching tattoos in Bray and shopped in Brown Thomas.
Kevin has vowed to keep quiet on what happened during their marriage - but said he "loved her to death" and was completely blindsided by her request for divorce in October 2006.
"Britney proposing to me on a plane three months after we met and getting married two months later was just us living in the moment.
"I really thought I’d spend the rest of my life with her… There were a few drastic things that went down, which I’ll never talk about, but overall we still had fun.
"So when she filed for divorce, I was completely caught off guard. Look, there are a million things I could say about her that would make huge headlines and cause a ton of drama, but for what? The truth is I loved her to death."
Federline said he could only watch from afar as Britney's life spiralled out of control in early 2007.
The star had a well publicised meltdown which saw her shave her head in a downtown Los Angeles barber in full glare of the paparazzi.
Her bizarre behaviour continued and she later lost physical custody of her two young sons to Federline.
In January 2008, Britney was placed on an involuntary psychiatric hold in UCLA after the police were called to her home. Infamously, she was pictured strapped to a guerney as she was stretchered out of her Hollywood Hills home.
A court later placed her under the conservatorship of her father Jamie Spears after he made an application.
She remains under the conservatorship today - but has gained freedom over her personal affairs, while some of her financial affairs remain under her father's control under terms laid down by the court.
Federline said it was tough watching his former wife plunge into despair from afar - and paid tribute to her father Jamie for the role he played in helping his daughter access the help she needed.
"It was extremely tough watching her go through a phase where she was clearly not OK right after the divorce.
"There’s a lot more I could have done to help. Taking full custody of the boys sucked the life out of me, but it was for them.
"I have to give Britney’s dad, Jamie, a lot of credit for saving her. He made it so I could actually deal with her again."
The former couple now have shared access of their two sons.
In 2013, Federline married volleyball player Victoria Prince. The couple have been together since 2008 and have two daughters together, aged three and 14 months. He also has a son and daughter from a previous relationship with actress Shar Jackson, from whom he split in 2004 prior to meeting Britney.
Britney is now in the middle of a well received residency in Las Vegas - and the money continues to roll in.