The 41-year-old revealed that when Emily, 23, moved in to his home, he didn't want to unsettle Princess, seven, and Junior, nine, - his children with ex Katie Price - so he and Emily didn't sleep in the same bed for a year.
"I didn't want the kids to get confused because they knew her as a friend," the dad-of-three explained.
"We still don't kiss in front of them now and we slept in separate beds for a year."
But despite Peter's best efforts to keep their relationship a secret – he didn't manage to fool Princess and Junior.
"I sat them down and said: 'Right kids, we need to talk. Me and Emily love each other. We've known each other for three years. I love her and I'll marry her one day,'" he said.
"Bista rolled her eyes and Junior said: 'Dad we're not stupid.'"
Emily, who is the mother of Peter's third child, 10-month-old Amelia, added: "I think we're quite protective because they're kids. We cuddle and we are more affectionate now. They're the ones saying: 'Dad, give Emily a kiss!'"
Peter previously told Parentdish that Princess had also figured out that he and Emily were engaged before he told her.
"I proposed on New Year's Eve and we wanted to wait for the right moment to tell them," he explained.
"But Bista turned round and went, "Er, hello! I already knew that. I've seen the ring on her finger for the last few weeks."
"I was like "How did you...? You are so intelligent." And she went, "I know!" She's a very bright girl. I love her so much, she's incredible.
"Junior was so happy too, but he was like, "Really?!'"He hadn't noticed the ring – like a typical guy!"
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