John Cena and Nikki Bella announced their breakup on Sunday, ending their six-year relationship and engagement, and bringing a shock to the wrestling world.

A source told People that Cena had "cold feet," as the wedding (scheduled to take place on May 5th in Mexico), and that he simply wasn't able to get his priorities "straight," which contributed to the end of their relationship.

The news was disappointing for a large portion of WWE fans, as Cena and Bella had been one of the biggest power couples in all of wrestling. But it's especially hard for Nikki's twin, Brie, who obviously grew very close to Cena.

On her Instagram story, Brie posted the following message:

“I’ll always love @johncena like a brother. He’ll always be family. My heart is hurting for he [sic] and my sister."

Brie and husband Daniel Bryan worked with Cena and Nikki to form the reality show, Total Bellas, which followed the personal lives of the WWE Talents. It was obvious that Cena grew extremely close to his future brother and sister in-law, so the breakup is hurting more than the 16-time World Champion and Nikki.

via wrestlingnewssource.com

The future of Total Bellas is immediately in question, and it's impossible to predict how both Cena and Bella will go about in their personal lives. Perhaps they stay together as friends, or perhaps the two move forward.

Cena proposed to Bella at WrestleMania 33, after they defeated Maryse and The Miz in a mixed tag match. This was despite Cena often stating that he wouldn't get married again, as he had a messy divorce with ex-wife, Elizabeth Huberdeau. She accepted, and the immediate assumption was that the two would live a happy and healthy life together.

But the breakup happened abruptly and unexpectedly, and fans can only hope both Cena and Bella can move on and find happiness as they move forward through this difficult time.

NEXT: JOHN CENA & NIKKI BELLA BREAKUP: BEST THEORIES ON WHAT HAPPENED