Brandon Blackstock, aged 48, died on 7 August from melanoma, a form of skin cancer.
Blackstock was the father of Kelly Clarkson's two children, and his death led Clarkson to postpone her Las Vegas residency shows.
Parton, whose own husband Carl Dean died in March, said: “I think that you just had to be grateful for the years that you’ve had with someone, and you just try to remember the very best of all that.”
Blackstock's family earlier said he had battled cancer for over three years and was a devoted father to his four children.