Nikki Bella's Bond With Sister's Baby Made John Cena Nervous Before Split

Nikki Bella called off her engagement to John Cena just weeks before the pair was set to walk down the aisle, and sources have said that the duo's differing views on marriage and children contributed to the split.

Those differences are clearly visible in a new clip from the upcoming season of Total Bellas, which sees Bella discuss putting a nursery in her and Cena's home for Bella's niece Birdie, an idea Cena is clearly not a fan of.

In the sneak peek, Bella's twin, Brie Bella, brings her daughter Birdie to visit Nikki and Cena at their home in San Diego, with Nikki getting some playtime in with her niece.

"I wish she was staying here," Nikki tells Brie. "We need to make it a nursery."

After making the suggestion, Nikki looks at Cena, who responds with a blank stare before turning his head away.

In an on-camera interview, Nikki admitted that her relationship with Birdie has put a new perspective on things.

"I just look at Birdie's face and never thought I could have this connection with a baby," she said. "I want to give her everything and make sure she has the greatest life. I've never felt that unconditional love."

At that point, Brie cut in to suggest that Nikki's bond with Birdie is a sign.

"Or Birdie is placed here on this planet to let you know you can have a connection like that with your own," she said.

Along with Birdie, Nikki is also aunt to brother JJ Garcia's daughter Vivienne, and the 34-year-old often posts on social media about how much she cares for her nieces.

"Coco's Hearts," she wrote next to a recent photo of the toddlers playing in her suitcase. "Love my little girls so much. And they love Coco's stuff. The best!"

Cena's position on children has been well chronicled on both Total Divas and Total Bellas, with the wrestler consistently having expressed that he does not want children.

However, during an appearance on the Today show this week, Cena seemed to switch gears, saying that he still loves Nikki and wants to have a family with her.

"For anyone out there speculating on what's going, on, I love her, I wanna be with her, I wanna make her my wife, I wanna be the father of her children," he said.

Total Bellas premieres Sunday on E! at 9 p.m. ET.

Photo Credit: Instagram / @thenikkibella