The 28-year-old actress, who renovated the house with now ex-husband Tao Ruspoli, says it did not feel like home for her anymore, reported Daily Star.
"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?'," she said.
Wilde says that she still has regrets about ending her marriage last year.
"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 is 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," she added.