The source asserted that since the two always kept their relationship out of the spotlight, not a lot of people knew that they were having troubles.
2018 was a big year for the Hollywood star as his directorial debut 'A Star Is Born' ended up being nominated for eight Academy Awards.
Earlier this year, accepting the award for best original music, Cooper thanked Shayk for "putting up" with him throughout the creative process.
"Most of all I have to thank Irina, for putting up with me for all the music I was trying to make in our basement for a year. Thank you very much. Thank you," he said.
After dating for about four years, Cooper and Shayk decided to call it quits.
The two welcomed their daughter named Lea De Seine in March 2017 but kept the news under wraps for a few weeks.
According to a report by Page Six, a source claimed that the two tried to make things work for the sake of their daughter, even though their relationship was hanging by a thread for months.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)