The pair, who dated for about five months, "have broken up and remain close friends," her rep says.
As for the reason for the split, a friend of McCarthy's tells PEOPLE, "Jenny has been very busy with work and with her in Los Angeles and Jason in Las Vegas, it became difficult to continue a long distance relationship."
In October, McCarthy, 38, raved about her good times with Toohey, 35. "I have been so open and truthful in this relationship – it is amazing," she told PEOPLE.
Her romance with Toohey, a Las Vegas-based performer and former model, thrived with mutual honesty, she said at the time.
"With Jason, I went in with all of my chips laid out," she said. "He respected that and saw the life in me. And, so far, it is working well."
In April, McCarthy and longtime boyfriend Jim Carrey revealed they had split after five years together.
With reporting by JULIE JORDAN