Their union infamously only lasted 55 hours before the paperwork was filed for it to be annulled. Now, Alexander is speaking out about the experience as Spears fights in court to end the conservatorship she's been under since 2008.
"What they did to Britney and me should have rung warning bells," the 39-year-old recalled to the Daily Mail about their relationship.
"The men in black swooped in, along with her mum and other family members, and they made us sign paperwork under duress to end our marriage. We didn’t want to annul it. They lied to us. It was always about controlling Britney and controlling her money," he claimed.
Alexander continued, "She’s been living a nightmare far worse than anyone can imagine for far longer than people realize."
Spears broke her silence about her conservatorship last month. She called the conservatorship "abusive" and claimed while under it for the past 13 years she's been forced to perform on stage against her will, not allowed to get married to her boyfriend, and denied being able to remove her contraception.
"My dad [Jamie Spears] and anyone involved in this conservatorship, and my management who played a huge role… they should be in jail," the "Toxic" singer said.
Alexander and Spears grew up in Kentwood, Louisiana together and were young and in love, he claimed.
"I was tricked by her mum, dad and lawyers into signing the annulment," Alexander alleged. "I was told our marriage could hurt Britney’s career. I loved her and was a naive kid who had been raised to trust and respect my elders, just like she had."
"We were told that if we still felt the same way about each other in six months, then we could have a big, white wedding. They strung me along for 30 days, which was how long it took to get the annulment finalized, so I couldn’t contest it, and then they changed Britney’s number so I couldn’t talk to her. There have always been dark forces in her life," he further claimed.
Spears was about to go on tour for her fourth studio album, "In the Zone."
Alexander said the idea to get hitched happened in the early morning. "We were in bed talking and she asked me to go on tour with her. I told her I couldn’t. I was at college on a football scholarship. Then she asked me to get married," he explained. "We felt like this was a way we could be together. Britney was already feeling trapped, with everyone making money out of her. We figured that if we were married, they would have to let us see each other."
Alexander remembered sneaking out of their hotel going to the courthouse.
"We lined up with other couples, even though it was five in the morning, and people started recognizing Britney and taking her picture," he said. "Then we went back to the chapel and the limo driver walked her down the aisle."
"Britney didn’t have any cash – even back then they didn’t give her access to her money. So I paid for the wedding, photos, and video," Alexander claimed. "We were on a high. We consummated the marriage in the limo on the way back to the hotel."
The businessman alleged that within hours "lawyers, publicity people and the management people" came to the hotel and separated the couple. "They took Britney in one room and put me in another, like a police interrogation," he claimed.
"When she came out, she was a different person. It was like they’d hypnotized her or something," he alleged. "Then they started putting all this paperwork in front of us to sign."
Alexander believes that moment is when Spears' team started to view her differently. "If she could rebel and sneak off to get married, they didn’t have enough control. That’s when they started really getting tough on her. She was put into a gilded prison."
All Alexander wanted to do, he says, is love Spears and "protect her."
The pop star ended up marrying backup dancer Kevin Federline later in 2004 until 2007. The exes share two sons: Sean, 15, and Jayden, 14.
"I hope she gets her freedom soon and can live her life the way she wants to," Alexander said. "All I have ever wanted is for Britney to be happy. I’ll never stop loving her."
Spears' mom, dad and reps did not immediately respond to Fox News' request for comment.
Fox News' Julius Young contributed to this report