A 28-year-old Canadian man was briefly arrested in connection with the allegations but then released without charge after no explosives were found aboard the plane, flying from Toronto to Karachi.
The cleared suspect was going to Pakistan to get married and his ex had called Canadian police warning he was carrying explosives because she was unhappy with their separation, tabloid Aftonbladet wrote.
"From what I understood, an ex came forward with the claim in connection with their separation. It was surely not a happy one," Stockholm police officer Håkan Westing, who could not be reached for comment Monday, told Aftonbladet.
"She had an evil eye on him," he said, adding that according to the cleared suspect's written statement he was going to get married in Pakistan.
Stockholm police spokesperson Kjell Lindgren told AFP Monday the man was travelling to Pakistan "for personal reasons," but could not confirm he was going to get married or that an angry ex had tipped off Canadian authorities.
"It's a theory," was all he would say.
Lindgren said the man, who was detained but then released without charge after his plane had already left for Pakistan, was expected to leave Sweden Monday.
Media had reported earlier Monday the man was blocked from leaving Sweden because no airlines would take him onboard.
"That's not true," Lindgren said. "I think its a misunderstanding. There was no place, is the information I got. It just didn't work out with the flights."
Lindgren said there were no direct flights from Sweden to Pakistan but that Swedish authorities would continue to help the man as quickly as possible.
Canadian police has said they are looking into whether the bomb alert they received was a "terrorist hoax."