The idea was prompted when Nicole caught Keith checking out the new photo shoot Maren recently took part in for the current issue of the magazine.
“Poor Nic was horrified,” says the source.
“She walked in on Keith in his office – and he had Maren sprawled all over his screen. He quickly tried to click off the page –but it was too late.”
The two women have been at odds since Keith personally chose Maren to tour with him three years ago, at a time when rumours abounded that his and Nic’s marriage was on the rocks.
“There were whispers that the pair of them were getting along famously while they were on the road together,” the insider adds.
“That’s why Nic has never trusted Keith near Maren and told him to stay away from her. But they have continued to work together from time to time, and even though Maren is now married, Nic still hates Keith spending time with her.
"To see him ogling Maren’s sexy Playboy pictures was a stab in the back, as far as Nic was concerned.”
It’s not the first time the pair have been on shaky ground due to Nicole’s jealousy issues.
“Keith is an attractive man – and women are always throwing themselves at him,” an insider told OK! magazine.
“Nicole has every right to feel threatened, but her accusations are driving him insane.”
Keith also is prone to bouts of jealousy at times, too.
"Nicole finds Keith’s jealousy totally off-base, but he won’t let it go, and the constant fighting has them at a breaking point,” they add.
Only last year the couple entered therapy to try and sort their issues.
In March 2018, Nicole and Keith headed to a five-day retreat in Vermont for what was reported at the time as “private counselling”.
“It was an extremely emotional and testing few days,” a source reveals.
For more, pick up the latest copy of New Idea on sale now!