The 'Total Divas' star admits it was tough when the couple - who have since called off their engagement - decided to go their separate ways as it was like they were married anyway.
Nikki said: ''I feel such a huge piece is just missing from me. It was just weird. First morning in six years not to talk to him, you know?''
And her sister Brie added: ''I mean, you guys were like married ... I just don't want him to be lonely. And I don't want him to regret not being a dad. And that's what makes me sad 'cause John feels like a brother and I hate thinking in my head that he's gonna be alone.
''You and I are such hard workers and there's times there's been zero payoff, but when you have a baby, even if Birdie wakes me up five times in one night, the way she holds me, the way she smells, it's like, you don't care. I want you to feel that.''
John - who has previously insisted he does not want children in the future - fully supports Nikki's decision to have a family one day but she wanted him to father her children.
Speaking in the preview clip for their show 'Total Bellas', she said: ''He told me, he sent me this text last night and he goes, 'The day you become a mom and look at your baby, I'm expecting to get the first thank you text.' But it's like, I wanted him to be the father of my kids.''