Curtis died Wednesday of cardiac arrest. He was 85.
"We were together 16 years; we had a great time up until yesterday," Jill Curtis told TV's "Inside Edition" Thursday. "He died peacefully surrounded by those who loved him … in his bedroom where he loved to be … I'm very happy we made the decision to bring him home from the hospital. He passed in his sleep."
The widow said she blames her husband's death on smoking, even though he quit many years ago.
"He had COPD and very bad lung problems from smoking," she noted. "About 30 years ago, he quit. But his lungs never worked the way they should've. So he was always fighting that. ... His heart survived many things that would have killed an ordinary man. This time his heart was ready to go."
Curtis' film credits include "The Defiant Ones," "Spartacus," "Some Like it Hot" and "Operation Petticoat."