“It would have been hard for Phoebe because Julie would have completely stuck by Sam ... and there’s talk she didn’t offer Phoebe much support,” the source added.
Several reports suggest the couple were consistently overwhelmed by family tension – which began as early as their 2015 wedding.
Over Christmas, Sam was spotted spending festivities with his famous brothers and Phoebe was noticeably absent.
A family snap posted by Sam’s sister-in-law Joanna Burgess, who is married to his brother George – raised eyebrows online as she described the celebration as the “best one yet.”
Following the speculation that it was aimed at Phoebe amid her marriage breakdown, Joanna took to the social platform to confirm this was not the case.
“No need to drag my family or I into any of this – thank you,” Joanna wrote.
“It is not in my nature to take a ‘dig at someone. Phoebe has never joined the ‘Burgess side for previous Christmas festivities therefore my # couldn’t possibly be aimed at her! This year was no different to last year on her behalf.
“My last year’s Christmas upload I used a similar caption as it was our son’s first Christmas, this year we had our daughter join the three of us hence it being the #bestoneyet!”
Sam and Phoebe have not commented on the matter.
The two are parents to one-month-old son Billy and daughter Poppy, who is almost 2.