"There's only so many tears your body will let you cry," Rizzo, Saget's widow, said in an interview with "Good Morning America" that aired Thursday.
"He had the biggest heart of anyone I'd ever known," she added. "He put everybody first. He did everything for everybody. If you had a problem, he was the first person that was going to take care of it and help you ... He was just the most absolutely wonderful husband that I ever could have dreamed of."
The "Full House" actor, 65, was found dead lying on his bed in a luxury hotel room in Florida. He had just kicked off his "I Don't Do Negative Comedy Tour" and celebrated online.
"I'm back in comedy like I was when I was 26. I guess I'm finding my new voice and loving every moment of it," he posted on Instagram before he died.
That night, he also reached out to Rizzo, texting her: "I love you so much, and I can't wait to see you tomorrow."
"What was the last conversation, phone call?" asked ABC News Correspondent T.J. Holmes during their interview at Rizzo's Los Angeles home.
"[He] was telling me what a wonderful show he had and how it was so amazing ... He was happy and loving what he did. It made him so happy, to bring laughter to people," she answered.
She described feeling sadness, shock and disbelief upon learning about her seemingly healthy husband's death. Saget was found with no signs of trauma or foul play, according to a sheriff's office report. It could take months for an autopsy report to determine the cause of death.
MORE: Autopsy performed as new report details circumstances of how Bob Saget was found
Rizzo called their love story a whirlwind that started when the two met the modern way: He sent her a direct message on social media. After dating three years, the couple married in 2018, with Saget turning their ceremony into a bit of a comedy act.
"Oh gosh. Bob did a minute of stand-up during our vows," she said, laughing. "And he just made me laugh so hard."
Rizzo said her late husband's three passions were his daughters, his comedy and his cause. Saget was a champion for the Scleroderma Research Foundation, motivated by the memory of his late sister, who died of the autoimmune disorder in 1994.
Close friend John Mayer and fellow "Full House" alums Candace Cameron Bure and Dave Coulier made sweatshirts to raise money for the charity. One reads, "Love like Jesus. Hug like Bob Saget," and Rizzo called it "very special."
"If you knew Bob, you know he gave the best hugs ... It was a very deep, meaningful hug. And then he would rest his head on your shoulder," Rizzo said.
Rizzo said she believes Saget achieved his life goal: To spread love and laughter.
"I'm just so proud of him because he truly brought people together. He was so wonderful, and I was so honored to be his wife and to be able to be a part of it and bring any bit of happiness that I could because he deserved it so much," she said.