The 'Voice' mentor former flames include catwalkers Anne Vyalitsyna and Nina Agdal, reported Us magazine.
"He apologized for how he treated them," a source said.
However, the ladies aren't quite so keen to let him off the hook.
"They couldn't care less he wants to make it right," the source added.
Engaged since July 2013, Levine, 35, and Prinsloo are expected to get married in Cabo San Lucas, Mexico, this summer.