In an exclusive interview with Closer Weekly — on newsstands now — Jason Ritter opens up about losing his father, John Ritter.

Jason tells Closer that his father’s death — which came unexpectedly in 2003 after John suffered an aortic dissection on the set of his TV series 8 Simple Rules at 54-years-old — has helped him “realize how fragile we all are.”

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Jason and John in 2003.

Jason admits to Closer that when his father died, his life went “downhill” immediately after that tragic loss. “But now I try to be happy. That’s what he would have wanted,” says Jason. “I try to live as honestly and simply as possible.”

RELATED: See Which Former 8 Simple Rules Star Just Welcomed Their First Baby!

“Of course, I wish things could have been different,” Jason tells Closer. “He was such wonderful man and I miss him always.”

jason ritter john ritter getty images

Jason and John in 2003.

“I feel his presence every day,” Jason confides to Closer. “Sometimes I will turn on the TV and catch an old episode of Three’s Company. I always watch it. Occasionally, there is even an episode I haven’t seen before. It’s special to be able to do that.”

“I do wish he’d been able to see all the things [I’ve done] since his death,” Jason admits to Closer. “I also think somewhere maybe he is seeing them and all the things in the future.”

For more from Jason, pick up the latest issue of Closer Weekly, on newsstands now!