The relationship was strained over Cooper's "intense" work ethic during production and the press for "A Star Is Born."
"He strives to improve himself and his career and not want distractions," the source said. "If he plays a role, he at least partially remains in the role throughout the filming."
Cooper (44) and Shayk (33) have separated after four years of relationship, a second source close to the couple told CNN.
But early in his time with Shayk, Cooper talked to friends about wanting to marry her.
"He said she was the one" in 2015, "said the first source, adding that the couple has been" going back and forth for about a year ", trying to work things for their well-being 2-year-old Daughter.
Cooper and Shayk recently visited Jerry Seinfeld's 65th birthday party at New York's Cafe Carlyle in late April.
In February, Shayk Glamor UK had communicated that she would not share her private life with the public.
"Me I have a lot of friends who share a lot of their private life on Instagram or on social media, "she said," I admire it and think it's great ̵
1; but I think it's all about it. "Personal Choice Because my work requires That I'm out there, I've just decided that my personal life will be quiet, that's why it's called personal because it's something for you and your family and I agree with that. " CNN joined Co opera and Shayk endeavored to comment.
Cooper's "A Star Is Born" co-star Lady Gaga has recently reported her split from her former fiancé Christian Carino in February.
"The last time I sang that song, I had a ring on my finger, so it will be different this time," Gaga reportedly said during a performance of her Las Vegas-based show "Jazz and Piano" over the weekend before she sang "Someone to Watch Over Me."
Gaga and Cooper's sensational duo "Shallow" at the Academy This year's awards have inspired fans to speculate and hope in social media that two could realize their on-screen romance.
Gaga responded with a big wink to the suggestions the two had.
"First … Social media is, quite frankly, the toilet of the internet and what it means to pop culture is profound," Gaga said in an interview with Jimmy Kimmell a few days after the show. "People have seen love and, guess what, we wanted to show you this, this is a love song." "From a performance standpoint, it was so important to us both that we were connected to each other all the time," Gaga said. "I wrapped my arms around Tony Bennett for three years when I was on a world tour, and when you sing love songs, you want people to feel that way."