"It's my family – my wife and twins," Peyton Manning, 37, told PEOPLE at Tuesday's Super Bowl XLVIII Media Day in Newark, N.J.
"My entire family keeps me positive and they always support me," says the Denver Broncos star of his wife of almost 13 years, Ashley, 39, and their 2½-year-olds, daughter Mosley and son Marshall. "They will be coming to town to be with me. Without them, I would not be where I am today. I am very grateful."
As the "excited" QB prepares for his third big game (his first cold-weather Super Bowl) in East Rutherford, N.J., Sunday against the Seattle Seahawks, he hopes to make history.
If Manning's Broncos emerge victorious Sunday, he will be the first starting quarterback to win two Super Bowls with two different teams. Manning won Super Bowl XLI with the Indianapolis Colts in 2007.
Off the field, Manning says he's happy spending time with his twins, who are just starting to talk.
"My kids provide me a lot of joy and happiness everyday," he said. "I'm learning more about them everyday. It makes me happy and excited."