While the two were initially diametrically opposed when it came to having children, something's changed.
In a sneak peek at Sunday's new episode of "Total Bellas," the two reunite for what looks like a romantic dinner and hash out their issues before Cena drops a bombshell.
"I don't think date nights can ever get old, but I think so many years down the road, to keep things exciting, I think kids help that in a relationship," Nikki tells him in the preview clip. "I see the point of kids after you've been with someone for so long."
Cena, who has been very open about his stance against having children in the past, responds, saying, "So basically, what you just said across the table is, you would get bored of me."
"I'm not going to get bored," she promises.
"In a hypothetical universe, say I was like, 'OK we're going to have kids,' and we do and you find out that wasn't the real problem. And then years from now you look at me and resent," he continues. "So I'm talking to you tonight and asking these difficult questions because I don't know if you're just upset that you're not going to be a mom or if you've fallen out of love with me. Because it kind of feels like both. There's no way I can interpret your actions over the last three months as anything different."
That comment seems to catch Bella by surprise, as she swears her only issue is that she "just wants to be a mom."
"I feel like there's so much more I want to do with you and experience with you," she adds. "It's just wanting to be a mom and knowing, like, you will not be a dad. So it's me who's stuck around thinking I can be OK with it and I just came to the realization that I'm not okay with it."
It's here that the gears switch in Cena's head.
"So it's literally just about being a mom? Okay, because I can't have you out of my life," he tells her. "Ever. And I wanna marry you. Relationship and marriage is about sacrifice, and I will make that sacrifice for you. I will give you a child."
While it's not exactly romantic to call having a baby "a sacrifice," we'll see where the conversation goes next when "Total Bellas" airs Sunday night at 9pm on E!