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Actress Olivia Wilde says she knew her marriage was over the day she and her now-ex-husband completed renovations on their new house, because it didn't feel like home for her.

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The "Tron: Legacy" star ended her eight-year marriage to Italian prince Tao Ruspoli last year.

In a frank TV chat on "The Conversation With Amanda de Cadenet," which aired on Thursday, May 31, the pretty star said, "We'd just finished a huge renovation on the house. ... We built a new house and it was perfect. ... The day it was finished is when I knew it wasn't the house. I think that I finally started being really honest with myself and that was the scariest thing to do. (I said), I am the luckiest person on Earth: There is this extraordinary person who is my partner in life, everything seems perfect, why aren't I happy?'

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I kept trying to do different things, change different things to make everyone happy, and I moved houses ... I changed all the outside stuff ... I thought, 'It's the house. It's wrong for us and it's making us something we're not and we've lost something'; and I thought, 'It's the environment. ... We need nature'; ... I kept thinking, 'We need grass.' We get the house, get the grass -- it's still not working, so I think, 'We've got to renovate the whole thing,' and I would literally walk into the room of a house that I bought because I loved ... and I'd say, 'I'm being decapitated; the house is decapitating me,' and he would say, 'OK, we'll bust up the ceilings.' He was really trying to accommodate all these requests."

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Wilde admits she still has regrets about ending her marriage: "You don't want to break up with someone, you don't want to end a marriage, especially if you really like the person. You just know that something's off and so you try to change everything else. The day I knew I had to ask for a divorce was the worst day of my life. ... I had no idea how to be alone."