The ex-TOWIE star was previously engaged to Marnie but told New magazine that after they split, he heard she'd kissed fellow Essex star Lewis on a night out.
Ricky said: "I know that when we first broke up, within a week she was seen in a cab with Lewis, and I was told they kissed. Because they've already hooked up and they've got the same management, it makes sense that they'd get together."
We reached out to Marnie and Lewis' rep for comment.
Their spokesperson did previously tell The Mirror, however, that the pair had definitely NOT hooked up before the show.
"Marnie had not pre planned any kind of romance in the house with Lewis," said the rep. "They have met once before they were even with the same agent. They were not aware of each other going into the house and haven't planned any kind of relationship for screen time."
Marnie and Lewis were pictured together at a Jeans For Genes charity event in London in 2015, shortly after Marnie's split from Ricky, but a rep for Lewis said at the time they'd just bumped into each other while out with mutual friends.
Meanwhile, Ricky also told New mag he was a tad peeved with Lewis for getting it on with Marnie, considering they both appeared in TOWIE together and had been friends.
"I feel a bit miffed because we were friends and used to get on," he said. "It's annoying that he's done that. Obviously I won't be talking to him any more. I wouldn't have gone with one of his exes, so I'll cut all ties."
Marnie and Lewis took their romance to the next step on the most recent episode of CBB, jumping into the shower together!
Cheeky Geordie Shore star Marnie joined Lewis in giving viewers a full frontal flash as they jumped into the shower together for what Marnie described as a very "romantic" moment.
But it was JUST a shower, she hastened to add.
"I just had the most romantic shower in my life! I would never do anything more than shower with him and kiss him," she said. "I've never had a boy treat me how he treats me! I feel so lucky. He is just perfect. I don't ever want to leave this house!"
Marnie will be hoping then that Lewis is safe in tonight's eviction. He's nominated against Saira Khan, Stephen Bear and Heavy D, and one of them will be going home in Tuesday evening's live show.
CBB continues tonight on Channel 5.