GETTING older isn’t easy, even for a blockbuster  action  hero like Bruce Willis.

Insiders say the 58-year-old “Die Hard” star now needs more than eight hours of sleep at night and can no longer do his own film stunts. He’s even admitted to pals: “I’m half the man I used to be.”

His upcoming sum­mer flick, “Red 2,” uses computerized simula­tion to perform action sequences that “would have been a breeze for Bruce six or seven years ago,” revealed a source. “He’s definitely slowing down, and has admitted that his schedule over the past year has been horrible for his health and mood. He needs a break.”

Several years ago, the aging thesp decided to “get in as much work as possible before it was too late.” Since 2008, he’s made 14 films, with more than five in development.

But the source says he had a change of heart last year after his wife, Emma, 36, gave birth to their daughter, Mabel.

“He’s all about quality of life now,” the source added. “He’s promised Emma he’ll slow things down so he can focus more on family – and that’s exactly what he’s doing.”