Last week it was reported that Bradley Cooper and Irina Shayk had called it quits after four years together, and though neither party has spoken out about the separation, a source explained to PEOPLE what part of the problem may have been.

“Bradley was emotionally absent during the long time filming A Star Is Born,” the insider explained. “They tried to save the relationship but it had changed.”

“Since Bradley and Irina have always been very private about their relationship few knew there was really for sure something going on,” they continued, referring to the couple's choice to keep their relationship private.

Though people are convinced Lady Gaga is to blame for the break up, but a source close to Cooper and Shayk shut that down while speaking to Entertainment Weekly.

"Things were difficult before Bradley started filming A Star Is Born but his dedication to his work while making the movie only made things harder at home," they said. "The constant speculation about Bradley's relationship with Gaga -- while things were difficult at home -- didn't help the situation. But his relationship with Gaga is not the issue. They have many daily issues as parents and as professionals and have been fighting."

"Their troubles have been going on for quite some time and they even considered splitting during the release of the movie," the source continued. "They talked things through a great deal and seemed to hold off and keep up appearances for the time being. It was recommended they delay a split at what seemed to be the peak of his career because the negative attention would take away from the excitement of the release."

Though Cooper and Shayk never married, they share a daughter together, 2-year-old Lea De Seine.

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