The 30-year-old former 'That 70s Show' star said her relationship with Kutcher, 36, is different from all the ones she had in the past, reported Contactmusic.
"I cried. I was a mess. Not to discredit any relationships in my past, but this relationship is different," she said.
"All of a sudden, it wasn't the same. And I was really proud of myself for acknowledging that," Kunis said, recalling the day Kutcher proposed her.
Kunis said before Kutcher she could easily say no to people but he changed it all for her.
"I was really good at saying no. I decided I was just going to say yes to any opportunity that came, no matter how crazy. And it changed my life."