The Most Shocking Celebrity Splits

Wedding planning wasn't exactly a breeze for these two, who butt heads over Cena's best man on this Sunday's "Total Bellas."

John Cena and Nikki Bella's wedding is off for now, and another sneak peek at the next episode of "Total Bellas" shows it was not smooth sailing as the couple inched toward the alter.

Our source of contention: the "Blockers" star's best man.

In a clip from this Sunday's new episode, Nikki confessed that she already picked out a best man for her fiancé, without consulting with the groom-to-be at all. "So, I may or may not have kinda jumped the gun and told Rob that he's your best man. I just assumed that if you were to have two best men it would be Rob and Johnny Martin," Nikki admitted.

"Now saying it, I kinda feel silly. Maybe I should have said this out loud before I actually did it," she added in a confessional, before the camera cut to Cena's less-than-enthused face.

After Cena asked if she just thought the two man would be his choice or if she actually talked to either of them about it, she added, "It's not like I gave them a gift and I was like, 'Hey it's official.' I just said you'll be John's best man." John's response: "That's pretty official to me, saying that they have the job, right?"

She attempted to alleviate the situation by joking "it's like I blew Christmas," but Cena was still clearly frustrated.

"This is no time for us to argue," Cena said. "This is a big thing for us, so I'll just say what's happened to far: You took that choice away from me and you took the meaning of me telling them."

"I guess what I'm trying to say is, one, let me know if you're going to make a decision on my behalf, especially one that directly affects me," he added, "and two, for God's sakes, be honest with me."

"Total Bellas" airs Sundays on E!

View Photos Getty John Cena, Nikki Bella and Apatow Clan Attend the 'Blockers' Premiere