The 44-year-old television personality dedicated a sweet post to Wahlberg on Thursday after helping raise $10,000 for charity in his name.
"To my sun and stars... you are my superman, my oxygen, my teacher, my future, & my one and only," McCarthy captioned a photo of herself with the Wahlburgers star.
"This world is a better place because of you and I am so honored to grow younger with you through the years. Happy Birthday @donniewahlberg," she added.
McCarthy and dozens of fans surprised Wahlberg by giving $10,673 to McCarthy's Generation Rescue organization for children with autism and the Remember Betty charity for breast cancer patients and survivors.
"So #Thankful to the greatest fans on the planet. Your love, support & generosity continue to amaze me. I love you!" Wahlberg tweeted.
"What's better than birthday balloons on @twitter? Reading thousands of birthdays message from all of you! It is so appreciated. #Thankful," he later added.
McCarthy married Wahlberg in August 2014 after a four-month engagement. She penned a love letter to the Wahlburgers star in July ahead of their third wedding anniversary Aug. 31.
"Never in my life have I met anyone who has gone out of their way physically, emotionally, spiritually and lovingly for the sake of others," she wrote. "I don't know anyone like you. And I never will. I just know how lucky I am to have you."