Levine "was blindsided," a source close to the 33-year-old Maroon 5 frontman -- who was home in Los Angeles when Vyalitsyna revealed the couple had ended their relationship while in New York City -- told Us Weekly in its April 16 issue.
"Adam's heartbroken. He wasn't even sure they were really broken up." As recently as late March, Levine reportedly "thought they were together!"
According to another Levine source, the 26-year-old Sports Illustrated swimsuit model handled the breakup very poorly because she gave the singer no notice.
"It was a cheap shot," the source told Us. "Anne didn't want it to look like he broke up with her."
While Vyalitsyna's decision to call it quits apparently stunned Levine, friends of the pair weren't as shocked when they learned the news.
"Anne said he didn't pay her enough attention," a source close to the Russian model said.
The couple reportedly spent quite a bit of time apart, as Vyalitsyna was staying in Miami late last month while Levine was working in Costa Rica. Vyalitsyna was also apparently looking to settle down despite Levine's hesitation to take their relationship to the next level.
"As a woman, you get to a point where you want to get married," an Us insider explained. "Adam wasn't ready to take that step."
However, Vyalitsyna isn't having much trouble moving on from Levine and is determined to find a suitable husband, Us reported.
"She's telling people she wants to meet guys!" another source close to the swimsuit model noted.