US media reports that the singer, 32, and her talent agent, 50, have amicably separated, two years after they began dating.
A source told People: "It just didn’t work out. Relationships sometimes end. There’s no long dramatic story.”
The Sun Online has contacted a representative for Gaga for comment.
Carino reportedly asked Gaga to be his wife months after they started dating in February 2017.
She didn't go public with the news until she flashed her ring and named her man as her fiance during a speech at Elle magazine's 25th annual Women in Hollywood Celebration in October.
The dazzling pink rock was reportedly worth £304,000,with Glamour describing it as "6-7 carat pink sapphire surrounded by a diamond halo of 3-4 carat diamonds".
This is Gaga's second failed engagement - she was previously planning to wed actor Taylor Kinney, 37, before they split at the end of 2016.
Rumours swirled about her latest romance earlier this month when the singer didn't wear her engagement ring to the Grammys - and Carino didn't show up as her date.
Last week Gaga celebrated Valentine's Day by getting herself a brand new rose tattoo on her back.
The star took to social media to show her fans the new inking, which takes up the whole of her spine, as a toast to La Vie en Rose - a famous french song that she sings in hit film A Star Is Born.
She wrote: "Happy Valentine’s Day. A tattoo toast to “la vie en rose” by the beautiful @winterstone my spinal cord is now a rose."
But her trip to the tattoo parlour didn't end there, as Lady Gaga, real name Stefani Joanne Angelina Germanotta, also got her musical note tattoo on her arm corrected, blaming the wonky line on 'too many tequilas'.
"Musical crisis averted. Too many tequilas forgot the fifth staff line poor thing. Here’s the real deal," she joked with a picture of the altered inking.
However, Gaga's impromptu trip to get a tattoo on a day where people celebrate their loved ones made fans speculate on her relationship with Carino.
One questioned: "Are the rumours about the break up true? I hope not. Just like the curse you referred in your documentary that once you won something you lost something as well."
While another said: "I noticed she hadn't been wearing her engagement ring."