Ronaldo singled out the United boss for criticism on TalkTV, saying he had no respect for Ten Hag and felt betrayed by the club.
United responded by bringing Ronaldo's second spell at Old Trafford to a hasty conclusion and Ten Hag has now opened up on his own feelings about the Portuguese star.
Speaking to reporters in Spain, where United are preparing for the return of domestic action, the Dutchman said of the interview: "I have seen most of it. I have to do it. It is part of my job.
"The interview, I think, as a club, you can't accept. To make that step, he knew the consequences. But before he never told me. Until that moment he never told me 'I want to leave'."
Ten Hag insisted he would have been happy for Ronaldo to stay and even to sign a new contract.
"Last year he scored 24 goals," said Ten Hag. "What does this team need? We need goals.
"I like to work with world-class players. I know they can make a difference and help you to achieve your objectives.
"I wanted him to stay from the first moment until now. I did everything to bring him into the team because I value his quality. We wanted him to be part of our project and for him to contribute to Manchester United because he is a great player and has such a great history."
With United gearing up for the return of the Premier League later this month, Ten Hag is determined to put the matter behind him and focus on the future.
"I don't want to spend energy on that," he said. "It is the past. We want a new future of Manchester United and he didn't want to be part of it."