John Cena and Nikki Bella's decision to separate and call off their engagement has left fans in tears, and while neither has explicitly stated the reasons for their heartbreaking decision, sources close to the couple have come forward with new details as to why this split was inevitable.

The former couple had been together for six years and were preparing to walk down the aisle on May 5, 2018.

John and Nikki No More 

According to sources, the couple's problems began when the pro wrestler began getting "cold feet" as the wedding date drew closer. Cena apparently "talked a good game" to his fiancée but it wasn't enough to keep the two together.

"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 source states

The source continued to suggest that Cena returning to his "selfish" ways was what ultimately pushed Nikki to the breaking point and that he should have never proposed to her. 

"He's an incredibly dedicated, driven, ambitious guy. 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 source continued. 

It has also been speculated that Cena was not looking to get married again after his tumultuous first marriage to Elizabeth Huberdeau.

Nikki shared the announcement on her Instagram page late Sunday evening.

We love you all ️ A post shared by Nikki Bella (@thenikkibella) on Apr 15, 2018 at 6:30pm PDT

Other Shocking Celebrity Splits

The wrestlers join a list of other shocking celebrity breakups that have made headlines since the beginning of 2018. On April 2, Jenna Dewan Channing Tatum announced their decision to "lovingly" separate after nine years of marriage.

In February 2018, Friends star Jennifer Aniston and her husband of two years, Justin Theroux, announced that they were separating. Former playmate Kendra Wilkinson and her husband, athlete Hank Wilkinson, also announced their separation and intention to divorce after nine years of marriage.