"Mike and I were very in love when we met," Duff, 27, tells the magazine. "We both really wanted to get married. I'd been working since the age of 11 or 12, so making that choice at a young age seemed right for me. Maybe it wasn't, but we spent the majority of our time together really happy."
Over time, however, the marriage fell apart and the couple separated in January 2013. "It wasn't working well enough to stay together, but there was still a lot of love involved," she says. "It was just a slow set-in of us not being the match that we used to be. I'm lucky for the person he is and I am, and how we decided to handle this."
Duff also says her failed relationship has changed her views on marriage. "I don't want to sound bitter because I'm definitely not, but I don't know if people are meant to be together forever."
She adds, "Things happen over a long relationship that you can't always fight. A marriage of 20 years, the accomplishment of that must feel really great, but there are also huge sacrifices. I just always want to fight for happiness."
Duff and Comrie, a former NHL hockey player, are parents to son Luca, who turns 3 this month. She next stars on the new TV Land comedy Younger, which premieres March 31 at 10/9c.
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