"You try to get through it, but it's a reality of life. I think it's important to get back and try to start reliving your life," said Stallone.
Sage Stallone, 36, was found dead in his Studio City home July 13. He became famous for playing Rocky's son.
"It's a horrible situation but time hopefully will heal," the grieving father said.
The cause of death remains under investigation. Autopsy results could take at least 10 weeks to come in, said Lt. Cheryl MacWillie with the coroner's office.
Stallone commented on his son's passing with "The Expendables 2" co-stars by his side. Stallone's latest movie will hit the box offices Friday.