The couple, who had gotten engaged in front of millions of fans at WrestleMania 33 in 2017, revealed the two had decided to separate after six years together in a statement on Instagram, shocking fans of them as a couple and of their wrestling careers.
But now that everyone has had time to process, it's easy to see where their relationship appeared to be splitting at the seams, from their fundamental difference of opinion on building a life together to their busy lives that often took them away from one another.
Keep scrolling to see all the hints the two were on the rocks you may have missed before.
Cena, who had been married before to high school sweetheart, Elizabeth Huberdeau, had already gone through a divorce in 2012 after first tying the knot in 2009.
Since then until his proposal to Bella, he had been vocal about not wanting to marry again. In an episode of Bella's E! reality show, Total Bellas, he revealed that he had Bella sign a 75-page agreement before they could even move in together.
The couple also had fundamentally different opinions on having children, with Bella wanting deeply to become a mother and Cena standing staunchly in opposition to the idea.
In a 2014 episode of Total Bellas, he was very blunt about his ideas to Bella.
“I’ve told you I don’t want to get married and I don’t want to have kids, and you do want to get married and you do want to have kids," he said. "I feel like there’s a time bomb over my head.”
In an interview with Rolling Stone in 2016, Cena revealed that he and Bella went to therapy over the issue.
"Look, I know I cannot handle raising a child," he told the magazine. "It's like with the dog. My biggest thing to Nicole about the dog was: Love dogs, but I can't contribute to taking care of one. I don't have the time. And just because everyone else is happy with children doesn't mean that's how I have to live."
"I've been upfront about this," he continued. "I just have things I need to get done. It's not negotiable. We've been to therapy over it. I don't think it will ever be over with. I'm stubborn as f**k and extremely selfish as well. I don't want kids, I don't want marriage. That's me just saying, 'Hey, this is my life and this is how I'm going to live.'"
During a preview of the upcoming season three of Total Bellas, the couple was shown in what appeared to be a serious argument about the future of their relationship.
"So we really want to call this off?" Bella asked Cena, both looking upset.
Cena later said during his appearance on the TODAY Show that the moment depicted was one of the "lowest lows" of his relationship with Bella.
“I can generalize it in saying in relationships you have points of disagreement and it was a point of disagreement where it seemed like we couldn’t get past it,” he explained to Hoda Kotb and Kathie Lee Gifford. “We got past it, and we’re back on.”
In March, Cena opened told Entertainment Tonight at the 2018 Kids' Choice Awards about their struggles that have played out on Total Bellas.
"It's a weird thing that our relationship is public for the world to know, [but] what a good takeaway for the folks at home -- relationships are tough," Cena said. "It's hard work, and a lot of times, it has to do with looking at yourself."
"'OK, there's a problem. Am I causing it? I kind of am. I'm being way too selfish here. We need to talk about this,' and that leads to a lot of conversations," he continued. "Sometimes people don't want to have those conversations."
With both of their busy schedules, the WWE couple often had a hard time chiseling out time in their lives for one another.
During an episode of Total Bellas in September, Bella's twin sister Brie told her that she doesn't consider Cena "family" because he didn't show up to their family functions.
“I just feel like, when it comes to family, John’s never in the picture,” Brie said. “Like, he’s always gone.”
“My man is part of this family, and I’m pretty much like his wife…” Nikki retorted.
“But you’re not his wife,” Brie said, cutting her off, revealing that she didn't want her daughter calling to Cena "uncle."
“You’re gonna be sad about that one day,” Nikki responded.
“Why?” Brie fired back. “It’s not like she’s ever going to meet him.”
Cena admitted to Us Weekly in March that it was hard for him and his then-fiancee to spend time together, and that they had to work extra hard to make their romance work.
“Anytime I get upset, I always just realize that I can’t live without her and I love her and that’s why I cave in on a lot of stuff. It takes being able to mesh two lives,” he said at the time. “She’s super busy and sometimes we don’t see each other for months at a time, but when we do see each other, it’s our time and it’s our time together. I think, for now at least, that is certainly what’s making this work.”
During an appearance on The Tonight Show Starring Jimmy Fallon, Cena revealed that he was on "standby" as far as a date goes.
“I was able to let Nicole plan the bachelorette party and she just finished that,” he said. “And now I’m just kind of on standby to know when it is and where it is, and I’ll be there.”
Nikki was the first to break the news on her Instagram:
"After much contemplation and 6 years of being together Nikki Bella and John Cena announced today their decision to separate as a couple," the statement read. "'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.'"2comments
The following morning, Cena tweeted out a statement presumably about the break-up.
"Hardship, loss, and humility are extremely difficult waters to navigate, but perseverance thru them builds a strength to withstand anything life throws your way," he wrote.