Jennifer Aniston and Justin Theroux were plagued by problems in their relationship well before they tied the knot — some of the same issues that ultimately led to their marriage’s demise, an insider tells PEOPLE.

The source close to the pair says that Aniston and Theroux each preferred different coasts, a major source of continued discord for the pair.

“Ever since they became serious, the living issue often made them bicker. It was always hard for Jen to understand why Justin didn’t like, or at least could learn to like L.A., when she was in L.A.,” the source says.

For a long time, the couple — who dated for more than four years before marrying in 2015 — accommodated each other, with Theroux spending more and more time on his own in New York City. “With Jen feeling so strongly about living in L.A. and disliking N.Y.C. so much, she wanted Justin to be happy and that’s why she agreed that he should spend so much time in N.Y.C.,” says the insider.

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Still the source adds that “one wonders why they got married in the first place” because “nothing really changed” after the pair tied the knot in a surprise backyard birthday party-turned-wedding ceremony on August 5, 2015, a few days before Theroux turned 44, followed by a honeymoon in Bora Bora with friends such as Courteney Cox, Jimmy Kimmel and Jason Bateman along for the trip.

Getting married “never seemed that important” to them, says the source. “When they finally did start to plan it seriously, it was more like ‘Let’s have a great party with all of our friends and go on a fun trip.’ ” Still, “they had the same issues before they got married as caused them to split.”

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Aniston, 49, and Theroux, 46, announced their split after seven years together and two and a half years of marriage with a statement released by Aniston’s longtime publicist on Thursday: “In an effort to reduce any further speculation, we have decided to announce our separation. This decision was mutual and lovingly made at the end of last year. We are two best friends who have decided to part ways as a couple, but look forward to continuing our cherished friendship.”

“Normally we would do this privately, but given that the gossip industry cannot resist an opportunity to speculate and invent, we wanted to convey the truth directly,” their statement continued. “Whatever else is printed about us that is not directly from us, is someone else’s fictional narrative. Above all, we are determined to maintain the deep respect and love that we have for one another. ”

Shortly before the breakup, a source told PEOPLE that Aniston and Theroux’s differing personalities and interests had put a strain on their marriage.

They are “very different people,” the source said.

“Jennifer loves her life in Los Angeles, and if anything, she has grown more attached to being there,” said an entertainment source. “Justin is not that comfortable or happy in Los Angeles all the time. He loves New York and always has.”

While the duo announced that they separated at the end of the last year, they celebrated the New Year together with their annual vacation to Cabo San Lucas, Mexico, alongside a handful of close pals including Jason Bateman and his family.