Inside John Cena & 'Heartbroken' Nikki Bella's Split: 'He Should've Never Proposed'

Wrestling superstar John Cena finally found an opponent he couldn’t beat – his own cold feet.

RadarOnline.com has learned the reason he called off his engagement to WWE Diva Nikki Bella.

“He’s an incredibly dedicated, driven, ambitious guy," an insider told People. "And for the longest time he said he didn’t think he had room in his life for a spouse or kids. It seems like in the end that was still the truth."

The insider added, “He talked a really good game about having changed, about having his priorities straight, about knowing what’s important, and that it was her. But as the day got closer, it was like he just went back to who he’s always been — which is someone who puts himself first, always.”

The couple were set to be married on May 5 in Mexico.

As RadarOnline.com reported, Cena, 40, and Bella 34, split ways after six years together.

“After much contemplation and 6 years of being together Nikki Bella and John Cena announced today their decision to separate as a couple,” read a statement on Bella’s Instagram. “While this decision was a difficult one, we continue to have a great deal of love and respect for one another. We ask that you respect our privacy during this time in our lives.”

Cena originally proposed to Bella last year in front of millions of people, at WrestleMania, the WWE’s biggest annual bash-fest.

"He never should’ve proposed," the insider said. "Let alone in front of millions of people. Now she’s heartbroken.”

Cena was previously married to Elizabeth Huberdeau from 2009 until 2012, and has said in the past he never wanted to get married again. The insider scolded him, saying that if he truly felt that way, he should never have proposed to Bella in the first place.

“This was supposed to be the happiest time of her life," the source said. "He ruined it and blew everything up.”