Weeks after rumors of their split made headlines, an insider offered insight into what allegedly went wrong, hinting that Randall tried to hold on to their relationship until he couldn't anymore.
"Bryan assured Sandra early on he'd stick with her through thick and thin," one insider spilled to a news publication. "He's done his best to keep his promise."
However, Randall, a professional photographer, began to feel overshadowed by his long-time partner's fame and fortune, which is an estimated $250 million, as the source continued, "Bryan's a self-employed photographer; she commands $20 million a movie."
"They used to go on dates to fancy restaurants and she'd pick up the tab because he couldn't afford to pay it. He began to resent it, and Sandra resented his resentment," the source added, before revealing that money was a "big issue for them."
In addition to money troubles, it seems Bullock also wasn't willing to welcome Randall all the way into her family. "The impression Sandra's friends have is that the kids are hers, not hers and his," the insider explained. "By her own admission, she doesn't really want to co-parent."
"A lot of times, Sandra has parented the kids in a way she felt was right without consulting Bryan, so his place in the household was taken down a peg or two," they claimed, as the Hollywood star was "more laid-back in some areas, while Bryan is more rigid."
And while Randall was ready to settle down and get engaged, The Proposal star "always managed to get busy with other things like work or the kids and it would fall through," said the source.
Bullock's cold feet inevitably became an issue for the pair. "For Bryan, being Sandra's husband and the kids' legal stepfather would have made him feel more legit," explained the insider, "but Sandra didn't really want that. She didn't want to lose control."
Making matters worse, things started to feel crowded at home after Bullock took a step back from her career earlier this year, with the source saying, "Sandra and Bryan were getting in each other's way and disagreeing over the smallest things."
Bullock and Randall have yet to publicly confirm their split, however, the insider pointed out the pair may not be done for good.
"The hope is they'll come to a point where they'll try to pull it together," concluded the source. "But in the meantime, Sandra's looking after the children and giving herself some time."
Bullock is mom to Louis, 12, and Laila, 10. She was previously married to Jesse James before their 2010 divorce.
Radar spoke to the source about what tore the couple apart.