"We don't [talk anymore]," Nikki says.

Yeah, that's done.

"He's doing him and I'm doing me," Nikki told ET at the iHeart Music Festival over the weekend.

Remember, John proposed to Nikki at WrestleMania 33 back in 2017 after years of dating -- but Nikki called it off in April. Cena tried like hell to get her back -- even making public pleas on national television -- but he couldn't pull off the comeback.

Now ... Nikki says she's 100% single -- but isn't ready for another man yet.

"I am single, but I'm not ready for mingling yet," Nikki said. "You know? I don't know."

Nikki says she's focusing on finding personal happiness before she jumps back in the dating pool ... and her sister is all for it.

"You gotta find yourself first," Brie Bella said.

One of the sticking points with Cena is the fact Nikki wanted kids -- and he didn't.

After she dumped him, John changed his tune and said he'd be open to it now ... but Nikki wasn't buyin' it.