Sources with direct knowledge tell TMZ ... since Theresa has an established career as a compliance officer in New Jersey, she grappled with the idea of leaving her job behind to move to Indiana or South Carolina with Gerry.

We're told Gerry understood Theresa's dilemma and offered up an idea -- splitting their time where they would spend six weeks in Jersey and six weeks in Indiana ... but they couldn't imagine a world where they could do that and Theresa could keep her job.

Our sources say Teresa didn't want to move to a small Indiana town or South Carolina and try to find work as a 70-year-old ... especially a job she loved like the one she has.

Ultimately, they couldn't meet in the middle ... so, they decided to end the marriage. They insist there are no hard feelings, and there's a lot of mutual love.

Gerry & Theresa made the shocking announcement Friday on "Good Morning America" ... telling the world they'd decided to split.

And, it seemingly came as a shock to many people who saw them in L.A. recently ... where sources tell us they were filming "Celebrity Family Feud" alongside their kids, families and other 'Golden Bachelor' contestants.

Turner filed for divorce hours after the announcement, citing an "irretrievable breakdown" of the marriage as the reason for the divorce.