The 63-year-old actress feels "responsible" for how disappointed people in the US were about her separation from the actor in 2009 after 23 years together, but she tries not to think about the impact it had on others.
Sarandon - who was born in New York - said: "The nation mourned. I had a lot of people who came up to me and were not as upset as I was - but were definitely upset.
"I did feel a sense of responsibility, because I knew that people had a certain idea of how I was and who we were. But on your deathbed, it's not really going to matter how those people felt."
The 'Enchanted' star also claims her opinions on relationships have evolved since she split from Tim - with whom she has two sons, Jack Henry, 21, and Miles Guthrie, 18 - and believes people need to see their personal relationships as "a breathing thing".
She added to New York magazine: "What I figured out is that the only mistake you can make is to think of your relationship to yourself or your work or your partner or your kids as something that becomes something. And then stays there.
"You have to see all of those relationships as a breathing thing. We're still parenting, although it's different when they're 18."